Chapter 4

Lines and Planes in Space

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Problem 353

Write the general equation of a plane from its parametric equations: x=u−6v,y=1+2u,z=2+3vx = u-6 v, y = 1+2 u, z = 2+3 v.

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Problem 354

Write the canonical equation of the line of intersection of the planes x+2y−z+2=0x+2 y-z+2 = 0 and 2x+y+z+1=02 x+y+z+1 = 0.

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Problem 355

A point M(1,2,3)M(1,2,3) is given. Write the equations of:

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(1)

the planes passing through MM and parallel to the coordinate planes;

(2)

the lines passing through MM and parallel to the coordinate axes;

(3)

the line joining the origin with the point MM.

Problem 356

Write the equation of the plane passing through the point (1,2,−3)(1,2,-3) and parallel to the vectors (1,−1,2)(1,-1,2) and (2,3,−1)(2,3,-1).

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Problem 357

Write the equation of the plane passing through the points (4,3,2),(5,2,4)(4,3,2),(5,2,4) and (1,−1,1)(1,-1,1).

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Problem 358

Find the parametric equations of the plane passing through the points (−2,1,1),(1,2,5)(-2,1,1),(1,2,5) and (−1,2,3)(-1,2,3), and write its general equation.

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Problem 359

Write the equation of the plane passing through three noncollinear points Mi(xi,yi,zi),i=1,2,3M_{i}\left(x_{i}, y_{i}, z_{i}\right), i = 1,2,3.

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Problem 360

Write the equation of the plane passing through the point (3,5,1)(3,5,1) and cutting off on the coordinate axes segments equal in length. The coordinate system is rectangular.

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Problem 361

Find the equation of the plane passing through the points (1,2,1)(1,2,1) and (3,1,1)(3,1,1) and parallel to the vector (−1,1,2)(-1,1,2).

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Problem 362

Write the equation of the plane passing through the points M1M_{1} and M2,Mi(xi,yi,zi)M_{2}, M_{i}\left(x_{i}, y_{i}, z_{i}\right), and parallel to the vector v=(α,β,γ)\mathbf{v} = (\alpha , \beta , \gamma ), not collinear with the vector M1M2→\overrightarrow {M_{1} M_{2}}.

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Problem 363

Set up the equations of the line that passes through the point A(1,−5,3)A(1,-5,3) and makes angles with the coordinate axes equal to π/3,π/4,2π/3\pi / 3, \pi / 4,2 \pi / 3, respectively. (The coordinate system is rectangular.)

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Problem 364

Find a direction vector of the line of intersection of the planes x−y+2z−1=0x-y+2 z-1 = 0 and 2x+3y−z+5=02 x+3 y-z+5 = 0.

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Problem 365

Find the parametric equations of the line of intersection of the plane 2x−y+3z−4=02 x-y+3 z-4 = 0 with the coordinate plane OxyO x y.

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Problem 366
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(1)

Set up the equations of the line ℓ\ell that cuts off on the axes OxO x and OyO y segments equal to 2 and 3, respectively.

(2)

Write the equation of the plane containing the line ℓ\ell and cutting off on the axis OzO z a segment equal to 5.

(3)

Write the equation of the plane containing the line ℓ\ell and parallel to the axis OzO z.

Problem 367

Set up the parametric equations of the line passing through the point (2,3,1)(2,3,1) parallel to the plane x−y−1=0x-y-1 = 0 and intersecting the axis OyO y.

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Problem 368

Set up the equation of the plane passing through the point MM and containing the line ℓ\ell:

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(1)

M(1,0,−1),ℓ:x−11=y−20=z−31M(1,0,-1), \quad \ell : \frac{x-1}{1} = \frac{y-2}{0} = \frac{z-3}{1};

(2)

M(2,−3,−1),ℓ:x=1+2t,y=−1−t,z=2−3tM(2,-3,-1), \ell : x = 1+2 t, y = -1-t, z = 2-3 t;

(3)

M(1,2,−2),ℓ:x+23=y+12=z1M(1,2,-2), \quad \ell : \frac{x+2}{3} = \frac{y+1}{2} = \frac{z}{1};

(4)

M(1,1,3),ℓ:2x+y−z+4=x−y+2z−4=0M(1,1,3), \quad \ell : 2 x+y-z+4 = x-y+2 z-4 = 0.

Problem 369

Find the equation of the plane containing the line ℓ\ell and parallel to the vector a\mathbf{a}, if:

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(1)

ℓ:x=−t,y=2−2t,z=−1+2t,a=(3,2,1)\ell : x = -t, y = 2-2 t, z = -1+2 t, \quad \mathbf{a} = (3,2,1);

(2)

ℓ:x+11=y−1−1=z−20,a=(2,2,−1)\ell : \frac{x+1}{1} = \frac{y-1}{-1} = \frac{z-2}{0}, \quad \mathbf{a} = (2,2,-1);

(3)

ℓ:2x+y−z+4=x−y+2z−4=0\ell : 2 x+y-z+4 = x-y+2 z-4 = 0, a=(1,3,−1)\mathbf{a} = (1,3,-1).

Problem 370

Find the equation of the plane parallel to the line ℓ\ell and passing through the points AA and BB, if:

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(1)

ℓ:x−1−1=y+23=z−21A(2,1,3),B(−2,2,1)\ell : \frac{x-1}{-1} = \frac{y+2}{3} = \frac{z-2}{1} A(2,1,3), \quad B(-2,2,1);

(2)

ℓ:x−y+3z+4=2x+3y−z−2=0,A(−2,2,1),B(0,4,3)\ell : x-y+3 z+4 = 2 x+3 y-z-2 = 0, A(-2,2,1), B(0,4,3).

Problem 371

Set up the equations of the line lying in the plane x+z=0x+z = 0 and intersecting the line

x−23=y−811=z−32 \frac{x-2}{3} = \frac{y-8}{11} = \frac{z-3}{2}

but having no common points with the line x=1+t,y=3+4t,z=−1−tx = 1+t, y = 3+4 t, z = -1-t.

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Problem 372

Pass a plane through the parallel lines

x−11=y+1−2=z−23,x1=y−1−2=z+23 \frac{x-1}{1} = \frac{y+1}{-2} = \frac{z-2}{3}, \quad \frac{x}{1} = \frac{y-1}{-2} = \frac{z+2}{3}
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Problem 373

In the plane passing through the three points M(1,1,−1)M(1,1,-1), N(−1,−1,−1),P(0,1,0)N(-1,-1,-1), P(0,1,0), an affine coordinate system is chosen with origin at the point MM and basis vectors MN→,MP→\overrightarrow {M N}, \overrightarrow {M P}. Find:

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(1)

the spatial coordinates x,y,zx, y, z of the point QQ of this plane whose plane coordinates are u=−1,v=2u = -1, v = 2;

(2)

the plane coordinates u,vu, v of the point of intersection of the given plane with the axis OzO z.

Problem 374

In the plane 2x+3y−4z+12=02 x+3 y-4 z+12 = 0 an affine coordinate system u,vu, v is chosen, whose origin is at the point SS of intersection of this plane with the axis OzO z, and whose basis vector endpoints are at the points P,QP, Q of intersection of the plane with the axes OxO x and OyO y, respectively.

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(1)

Find the spatial coordinates x,y,zx, y, z of the point EE of this plane whose plane coordinates are u=1,v=1u = 1, v = 1.

(2)

Write, in the plane coordinate system, the equations of the lines PQ,QSP Q, Q S and SPS P.

(3)

Write, in the plane coordinate system, the equation of the line of intersection of the given plane with the plane 5x+3z−8=05 x+3 z-8 = 0.

Problem 375

Three lines are given

{x=3+ty=−1+2tz=4t{x=−2+3ty=−1z=4−t{x−3y+z=0x+y−z+4=0 \begin{cases} x = 3 + t \\ y = - 1 + 2 t \\ z = 4 t \end{cases} \quad \begin{cases} x = - 2 + 3 t \\ y = - 1 \\ z = 4 - t \end{cases} \quad \begin{cases} x-3 y+z = 0 \\ x+y-z+4 = 0 \end{cases}

Write the equations of the line intersecting the first two of the given lines and parallel to the third.

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Problem 376

Write the equations of the line passing through the point (1,2,3)(1,2,3) and intersecting the lines x2=y+1−2=z−21,x4=y+20=z3\frac{x}{2} = \frac{y+1}{-2} = \frac{z-2}{1}, \frac{x}{4} = \frac{y+2}{0} = \frac{z}{3}.

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Problem 377

Set up the equations of the projection of the line x−23=y−1−2=z1\frac{x-2}{3} = \frac{y-1}{-2} = \frac{z}{1} from the point (1,2,1)(1,2,1) onto the plane y−2z+4=0y-2 z+4 = 0.

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Problem 378

Prove that the six planes, each of which passes through an edge of a tetrahedron and the midpoint of the opposite edge, meet at one point.

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Problem 379

Determine which of the following pairs of planes intersect, are parallel, or coincide. If the planes intersect, find the canonical equations of the line of intersection:

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(1)

x+2y−z+1=0,x+y−2z+1=0x+2 y-z+1 = 0, \quad x+y-2 z+1 = 0

(2)

x−3y+7z+1=0,3x−9y+21z+3=0x-3 y+7 z+1 = 0, \quad 3 x-9 y+21 z+3 = 0;

(3)

x−3y+2z+2=0,2x−6y+4z+5=0x-3 y+2 z+2 = 0, \quad 2 x-6 y+4 z+5 = 0;

(4)

{x=1+2u+v,y=3u+2v,z=−1+u+v;{x=4u+3v,y=−2+u−4v,z=3+u+2v;\begin{cases} x = 1+2 u+v, \\ y = 3 u+2 v, \\ z = -1+u+v ; \end{cases} \quad \begin{cases} x = 4 u+3 v, \\ y = -2+u-4 v, \\ z = 3+u+2 v ; \end{cases}

(5)

{x=−3+u+2v,y=−v,z=u;{x=1+3u,y=2−u+v,z=8+u+2v;\begin{cases} x = -3+u+2 v, \\ y = -v, \\ z = u ; \end{cases} \begin{cases} x = 1+3 u, \\ y = 2-u+v, \\ z = 8+u+2 v ; \end{cases}

(6)

{x=−3+u+4v,y=3+u+v,z=2+u+2v;x+2y−3z+2=0\begin{cases} x = -3+u+4 v, \\ y = 3+u+v, \\ z = 2+u+2 v ; \end{cases} \quad x+2 y-3 z+2 = 0.

Problem 380

In each of the following cases, determine whether the line ℓ\ell lies in the plane PP, is parallel to the plane PP, or intersects it; in the last case, find the point of intersection of the line and the plane:

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(1)

ℓ:x−1−1=y+27=z+17\ell : \frac{x-1}{-1} = \frac{y+2}{7} = \frac{z+1}{7}, P:7x+2y−z+7=0P: 7 x+2 y-z+7 = 0;

(2)

ℓ:x0=y−22=z+11\ell : \frac{x}{0} = \frac{y-2}{2} = \frac{z+1}{1},

P:5x−y+6z=0 P: 5 x-y+6 z = 0
(3)

ℓ:x1=y−11=z+11\ell : \frac{x}{1} = \frac{y-1}{1} = \frac{z+1}{1},

P:x−3y+2z+5=0 P: x-3 y+2 z+5 = 0
(4)

ℓ:x−3y+1=0,2x+y−5=0,P:x+2y−2z−2=0\ell : x-3 y+1 = 0,2 x+y-5 = 0, \quad P: x+2 y-2 z-2 = 0;

(5)

ℓ:x+2y+z−1=0,x+y−2=0,P:3x+2y−z−6=0\ell : x+2 y+z-1 = 0, x+y-2 = 0, P: 3 x+2 y-z-6 = 0.

Problem 381

Determine the relative position of the two lines in each of the following cases (they may: a) intersect, b) be parallel, c) be skew, d) coincide):

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(1)

{x=1+2t,y=7+t,z=3+4t;{x=6+3ty=−1−2tz=−2+t\begin{cases} x = 1+2 t, \\ y = 7+t, \\ z = 3+4 t ; \end{cases} \begin{cases} x = 6+3 t \\ y = -1-2 t \\ z = -2+t \end{cases}

(2)
(3)

x=t,y=−8−4t,z=−3−3t;{2x−y+2z=0,x+y−z=0;x = t, y = -8-4 t, z = -3-3 t ; \quad \begin{cases} 2 x-y+2 z = 0, \\ x+y-z = 0 ; \end{cases}

(4)

x=3+t,y=−1+2t,z=4;{x−3y+z=0,x+y−z+4=0x = 3+t, y = -1+2 t, z = 4 ; \quad \begin{cases} x-3 y+z = 0, \\ x+y-z+4 = 0 \end{cases}

(5)

{x+y+z−1=0,y+4z=0;,{2x+3y+6z−6=0,3x+4y+7z=0.\begin{cases} x+y+z-1 = 0, \\ y+4 z = 0 ; \end{cases}, \begin{cases} 2 x+3 y+6 z-6 = 0, \\ 3 x+4 y+7 z = 0. \end{cases}

Problem 382

Two planes are given

A1x+B1y+C1z+D1=0,A2x+B2y+C2z+D2=0 A_{1} x+B_{1} y+C_{1} z+D_{1} = 0, \quad A_{2} x+B_{2} y+C_{2} z+D_{2} = 0

Using the ranks rr and RR of the matrices

[A1B1C1A2B2C2] and [A1B1C1D1A2B2C2D2] \left[\begin{smallmatrix} A_{1} & B_{1} & C_{1} \\ A_{2} & B_{2} & C_{2} \end{smallmatrix}\right] \text{ and }\left[\begin{smallmatrix} A_{1} & B_{1} & C_{1} & D_{1} \\ A_{2} & B_{2} & C_{2} & D_{2} \end{smallmatrix}\right]

respectively, find the necessary and sufficient conditions for the planes to:

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(1)

intersect;

(2)

be parallel;

(3)

coincide.

Problem 383

Two planes are given by their parametric equations

x=x1+a1u+a2v,x=x2+a3u+a4vy=y1+b1u+b2v,y=y2+b3u+b4vz=z1+c1u+c2v;z=z2+c3u+c4v \begin{array}{ll} x = x_{1}+a_{1} u+a_{2} v, & x = x_{2}+a_{3} u+a_{4} v \\ y = y_{1}+b_{1} u+b_{2} v, & y = y_{2}+b_{3} u+b_{4} v \\ z = z_{1}+c_{1} u+c_{2} v ; & z = z_{2}+c_{3} u+c_{4} v \end{array}

Using the ranks rr and RR of the matrices

[a1a2a3a4b1b2b3b4c1c2c3c4] and [a1a2a3a4x2−x1b1b2b3b4y2−y1c1c2c3c4z2−z1] \left[\begin{smallmatrix} a_{1} & a_{2} & a_{3} & a_{4} \\ b_{1} & b_{2} & b_{3} & b_{4} \\ c_{1} & c_{2} & c_{3} & c_{4} \end{smallmatrix}\right] \quad \text{ and }\left[\begin{smallmatrix} a_{1} & a_{2} & a_{3} & a_{4} & x_{2}-x_{1} \\ b_{1} & b_{2} & b_{3} & b_{4} & y_{2}-y_{1} \\ c_{1} & c_{2} & c_{3} & c_{4} & z_{2}-z_{1} \end{smallmatrix}\right]

respectively, express the necessary and sufficient conditions for the planes to:

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(1)

intersect;

(2)

be parallel;

(3)

coincide.

Problem 384

A plane Ax+By+Cz+D=0A x+B y+C z+D = 0 and a line

x−x0a=y−y0b=z−z0c. \frac{x-x_{0}}{a} = \frac{y-y_{0}}{b} = \frac{z-z_{0}}{c}.

are given. Find the necessary and sufficient conditions for the line to:

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(1)

intersect the plane;

(2)

be parallel to it;

(3)

lie in the plane.

Problem 385

Two lines are given

x−x1a1=y−y1b1=z−z1c1,x−x2a2=y−y2b2=z−z2c2 \frac{x-x_{1}}{a_{1}} = \frac{y-y_{1}}{b_{1}} = \frac{z-z_{1}}{c_{1}}, \quad \frac{x-x_{2}}{a_{2}} = \frac{y-y_{2}}{b_{2}} = \frac{z-z_{2}}{c_{2}}

Using the ranks rr and RR of the matrices

[a1a2b1b2c1c2] and [a1a2x2−x1b1b2y2−y1c1c2z2−z1] \left[\begin{smallmatrix} a_{1} & a_{2} \\ b_{1} & b_{2} \\ c_{1} & c_{2} \end{smallmatrix}\right] \quad \text{ and }\left[\begin{smallmatrix} a_{1} & a_{2} & x_{2}-x_{1} \\ b_{1} & b_{2} & y_{2}-y_{1} \\ c_{1} & c_{2} & z_{2}-z_{1} \end{smallmatrix}\right]

respectively, express the conditions necessary and sufficient for these lines to:

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(1)

be skew;

(2)

intersect;

(3)

be parallel;

(4)

coincide.

Problem 386

Two lines are given

x−x0a=y−y0b=z−z0c,{A1x+B1y+C1z+D1=0A2x+B2y+C2z+D2=0 \frac{x-x_{0}}{a} = \frac{y-y_{0}}{b} = \frac{z-z_{0}}{c}, \quad \begin{cases} A_{1} x+B_{1} y+C_{1} z+D_{1} = 0 \\ A_{2} x+B_{2} y+C_{2} z+D_{2} = 0 \end{cases}

Find the necessary and sufficient conditions for them to:

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(1)

be skew;

(2)

intersect;

(3)

be parallel;

(4)

coincide.

Problem 387

Find the locus of points dividing, in one and the same ratio λ\lambda, segments with endpoints on two given skew lines.

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Problem 388

Three planes are given:

A1x+B1y+C1z+D1=0,A2x+B2y+C2z+D2=0A3x+B3y+C3z+D3=0 \begin{gathered} A_{1} x+B_{1} y+C_{1} z+D_{1} = 0, \quad A_{2} x+B_{2} y+C_{2} z+D_{2} = 0 \\ A_{3} x+B_{3} y+C_{3} z+D_{3} = 0 \end{gathered}

Let rr and RR be the ranks of the matrices

[A1B1C1A2B2C2A3B3C3] and [A1B1C1D1A2B2C2D2A3B3C3D3] \left[\begin{smallmatrix} A_{1} & B_{1} & C_{1} \\ A_{2} & B_{2} & C_{2} \\ A_{3} & B_{3} & C_{3} \end{smallmatrix}\right] \text{ and }\left[\begin{smallmatrix} A_{1} & B_{1} & C_{1} & D_{1} \\ A_{2} & B_{2} & C_{2} & D_{2} \\ A_{3} & B_{3} & C_{3} & D_{3} \end{smallmatrix}\right]

respectively; ri,Rir_{i}, R_{i} the ranks of the matrices obtained from the given ones by deleting the ii-th row, i=1,2,3i = 1,2,3. Express, in terms of r,R,ri,Rir, R, r_{i}, R_{i}, the necessary and sufficient conditions for:

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(1)

the three planes to have a unique common point;

(2)

the three planes to be pairwise distinct and to have a unique common line;

(3)

the three planes to intersect pairwise, with the line of intersection of each two planes parallel to the third plane (i.e., for the planes to form a prism);

(4)

two planes to be parallel, and the third plane to intersect them;

(5)

the three planes to be pairwise parallel;

(6)

two planes to coincide, and the third to intersect them;

(7)

two planes to coincide, and the third plane to be parallel to them;

(8)

the three planes to coincide.

Problem 389

Determine the relative position of the three planes in each of the following cases:

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(1)

x+2y−z+7=0,x+y−2z+4=0,5x+3z+2=0x+2 y-z+7 = 0, \quad x+y-2 z+4 = 0, \quad 5 x+3 z+2 = 0;

(2)

5x−3y+7z+10=0,x−y+6z+1=0,10x−6y+14z+9=05 x-3 y+7 z+10 = 0, x-y+6 z+1 = 0, \quad 10 x-6 y+14 z+9 = 0;

(3)

x−3y+2z+2=0,2x−6y+4z+3=0,5x−15y+10z+16=0x-3 y+2 z+2 = 0, \quad 2 x-6 y+4 z+3 = 0, \quad 5 x-15 y+10 z+16 = 0;

(4)

x+2y−z+7=0,x+y−2z+4=0,x−y−4z−2=0x+2 y-z+7 = 0, \quad x+y-2 z+4 = 0, \quad x-y-4 z-2 = 0;

(5)

5x−2y+3=0,3x+z−6=0,8x−2y+z+6=05 x-2 y+3 = 0, \quad 3 x+z-6 = 0, \quad 8 x-2 y+z+6 = 0;

(6)

x−y+2z+3=0,6x−3y+z−4=0,2x−2y+4z+6=0x-y+2 z+3 = 0, \quad 6 x-3 y+z-4 = 0,2 x-2 y+4 z+6 = 0.

Problem 390

Under what necessary and sufficient condition do the four planes

A1x+B1y+C1z+D1=0,A2x+B2y+C2z+D2=0A3x+B3y+C3z+D3=0,A4x+B4y+C4z+D4=0 \begin{array}{ll} A_{1} x+B_{1} y+C_{1} z+D_{1} = 0, & A_{2} x+B_{2} y+C_{2} z+D_{2} = 0 \\ A_{3} x+B_{3} y+C_{3} z+D_{3} = 0, & A_{4} x+B_{4} y+C_{4} z+D_{4} = 0 \end{array}

form a tetrahedron?

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Problem 391

Four planes are given

A1x+B1y+C1z+D1=0,A2x+B2y+C2z+D2=0A3x+B3y+C3z+D3=0,A4x+B4y+C4z+D4=0 \begin{array}{ll} A_{1} x+B_{1} y+C_{1} z+D_{1} = 0, & A_{2} x+B_{2} y+C_{2} z+D_{2} = 0 \\ A_{3} x+B_{3} y+C_{3} z+D_{3} = 0, & A_{4} x+B_{4} y+C_{4} z+D_{4} = 0 \end{array}

Using the ranks rr and RR of the matrices

[A1B1C1A2B2C2A3B3C3A4B4C4] and [A1B1C1D1A2B2C2D2A3B3C3D3A4B4C4D4] \left[\begin{smallmatrix} A_{1} & B_{1} & C_{1} \\ A_{2} & B_{2} & C_{2} \\ A_{3} & B_{3} & C_{3} \\ A_{4} & B_{4} & C_{4} \end{smallmatrix}\right] \text{ and }\left[\begin{smallmatrix} A_{1} & B_{1} & C_{1} & D_{1} \\ A_{2} & B_{2} & C_{2} & D_{2} \\ A_{3} & B_{3} & C_{3} & D_{3} \\ A_{4} & B_{4} & C_{4} & D_{4} \end{smallmatrix}\right]

respectively, express the conditions necessary and sufficient for these planes to belong to:

?
(1)

one bundle;

(2)

one proper bundle;

(3)

one improper bundle.

Problem 392

Let Πi(i=1,2,3,4)\Pi_{i}(i = 1,2,3,4) be planes with equations Aix+Biy+Ciz+Di=0A_{i} x + B_{i} y+C_{i} z+D_{i} = 0, every three of which meet at one point, but which have no common point altogether. Prove that any function of the form Ax+By+Cz+DA x+B y+C z+D can be represented as a linear combination of the left-hand sides of the equations of the planes Πi\Pi_{i}, i.e., there exist constants λi\lambda_{i} such that

Ax+By+Cz+D=∑i=14λi(Aix+Biy+Ciz+Di) A x+B y+C z+D = \sum _{i = 1}^{4} \lambda _{i}\left(A_{i} x+B_{i} y+C_{i} z+D_{i}\right)
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Problem 393

Describe all quadruples

Πi:{Aix+Biy+Ciz+Di=0},i=1,2,3,4 \Pi _{i}:\left\{ A_{i} x+B_{i} y+C_{i} z+D_{i} = 0\right\} , \quad i = 1,2,3,4

of planes in space possessing the following property: any function of the form Ax+By+Cz+DA x+B y+C z+D can be represented as a linear combination of the left-hand sides of the equations of the planes Πi\Pi_{i}, i.e., there exist constants λi\lambda_{i} such that

Ax+By+Cz+D=∑i=14λi(Aix+Biy+Ciz+Di) A x+B y+C z+D = \sum _{i = 1}^{4} \lambda _{i}\left(A_{i} x+B_{i} y+C_{i} z+D_{i}\right)
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Problem 394
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(1)

Describe all possible families of planes whose equations Ax+By+Cz+D=0A x+B y+C z+D = 0 can be represented as linear combinations

Ax+By+Cz+D=∑i=13λi(Aix+Biy+Ciz+Di) A x+B y+C z+D = \sum _{i = 1}^{3} \lambda _{i}\left(A_{i} x+B_{i} y+C_{i} z+D_{i}\right)

of the equations Aix+Biy+Ciz+Di=0A_{i} x+B_{i} y+C_{i} z+D_{i} = 0 of three fixed planes Πi(i=1,2,3)\Pi_{i}(i = 1,2,3).

(2)

Do the same for four planes.

Problem 395

Set up the equation of the plane containing the line of intersection of the planes Π1,Π2\Pi_{1}, \Pi_{2} and passing through the point MM:

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(1)

Π1:x+y−z−1=0,Π2:2x−3y−3z−2=0,M(1,0,−2)\Pi_{1}: x+y-z-1 = 0, \quad \Pi_{2}: 2 x-3 y-3 z-2 = 0, M(1,0,-2);

(2)

Π1:2x−y+3z−2=0,Π2:x+y−2z−1=0,M(2,1,−3)\Pi_{1}: 2 x-y+3 z-2 = 0, \Pi_{2}: x+y-2 z-1 = 0, \quad M(2,1,-3).

Problem 396

Set up the equation of the plane passing through the line of intersection of the planes x−2y+z−1=0,2x−3y+4z−5=0x-2 y+z-1 = 0,2 x-3 y+4 z-5 = 0 and parallel to the vector (3,2,−2)(3,2,-2).

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Problem 397

Set up the equation of the plane passing through the line of intersection of the planes 2x−y+5z−4=0,y−7z+12=02 x-y+5 z-4 = 0, y-7 z+12 = 0 and cutting off on the axes OxO x and OzO z equal nonzero segments.

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Problem 398

Show that the planes

Π1:x−y+z+1=0,Π2:2x+3y−z+2=0Π3:x=0,Π4:x+2y−z+1=0 \begin{array}{ll} \Pi _{1}: x-y+z+1 = 0, & \Pi _{2}: 2 x+3 y-z+2 = 0 \\ \Pi _{3}: x = 0, & \Pi _{4}: x+2 y-z+1 = 0 \end{array}

form a tetrahedron. Pass a plane through the line of intersection of the planes Π1\Pi_{1} and Π2\Pi_{2} parallel to the line of intersection of Π3\Pi_{3} and Π4\Pi_{4}.

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Problem 399

Write the equation of the plane passing through the point with coordinates (2,−1,−3)(2,-1,-3) and parallel to the lines of intersection of the planes Π1\Pi_{1} and Π2\Pi_{2}, and of the planes Π3\Pi_{3} and Π4\Pi_{4}, where the planes Π1,Π2,Π3\Pi_{1}, \Pi_{2}, \Pi_{3} and Π4\Pi_{4} are given by the equations x+y−z+2=0,2x−y+3z−1=0x+y-z+2 = 0,2 x-y+3 z-1 = 0, 3x+2y+z−4=03 x+2 y+z-4 = 0 and x+3y+2z−2=0x+3 y+2 z-2 = 0, respectively.

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Problem 400

Write the equation of the plane parallel to the lines of intersection of the planes Π1,Π2\Pi_{1}, \Pi_{2} and Π3,Π4\Pi_{3}, \Pi_{4} and equidistant from these two lines; the planes Πi(i=1,2,3,4)\Pi_{i}(i = 1,2,3,4) are the same as in the preceding problem.

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Problem 401

Set up the equation of the plane passing through the axis OzO z and equidistant from the points (2,3,−10)(2,3,-10) and (1,−3,19)(1,-3,19).

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Problem 402

The vertices of a tetrahedron P(3,5,−1),Q(7,5,3),R(9,−1,5)P(3,5,-1), Q(7,5,3), R(9,-1,5), S(5,3,−3)S(5,3,-3) are given. Write the equations of the planes equidistant from all vertices of the tetrahedron PQRSP Q R S.

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Problem 403

Set up the equation of the line that passes through the point (1,2,−1)(1,2,-1) and intersects the lines

{x−z=03x−2y−3=0;{2x−y+1=0x+2y−z+3=0 \begin{cases} x - z = 0 \\ 3 x - 2 y - 3 = 0 ; \end{cases} \quad \begin{cases} 2 x-y+1 = 0 \\ x+2 y-z+3 = 0 \end{cases}
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Problem 404

Show that the three planes x+2y−z−4=0,3x−2y+3z−6=0,4y−3z+3=0x+2 y-z-4 = 0,3 x-2 y + 3 z-6 = 0,4 y-3 z+3 = 0 form a prism, and write the equation of the plane passing through the line of intersection of the first two faces of the prism and parallel to the third.

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Problem 405

Through the point P(−1,2,3)P(-1,2,3) pass a plane so that in the triangle cut off on it by the coordinate planes, the point PP is the point where the medians meet.

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Problem 406

Let Πi(i=1,2,3)\Pi_{i}(i = 1,2,3) be planes with equations Aix+Biy+Ciz+Di=0A_{i} x+B_{i} y + C_{i} z+D_{i} = 0, meeting at one point, and let P(x0,y0,z0)P\left(x_{0}, y_{0}, z_{0}\right) be a point not lying in any of the planes Πi\Pi_{i}. Write the equation of the plane Π\Pi intersecting the planes Πi\Pi_{i} and passing through the point PP such that the latter is the point where the medians meet of the triangle in the plane Π\Pi, bounded by the lines of intersection of the plane Π\Pi with the planes Πi\Pi_{i}.

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Problem 407

Which two of the three points A(0,2,−1),B(0,−3,2),C(−3,2,1)A(0,2,-1), B(0,-3,2), C(-3,2,1) lie on the same side of the plane 3x+2y+z+1=03 x+2 y+z+1 = 0?

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Problem 408

Which of the two planes x+2y+4z−11=0x+2 y+4 z-11 = 0 and x−y+3z−9=0x-y+3 z-9 = 0 separates the points A(1,3,−1)A(1,3,-1) and B(5,−3,1)B(5,-3,1)?

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Problem 409

Two points A(1,3,−1)A(1,3,-1) and B(5,3,1)B(5,3,1) and a plane x−4y+2z−7=0x-4 y + 2 z-7 = 0 are given. Determine whether the given plane intersects the segment ABA B, its extension beyond the point AA, or beyond the point BB.

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Problem 410

Two points P(x1,y1,z1)P\left(x_{1}, y_{1}, z_{1}\right) and Q(x2,y2,z2)Q\left(x_{2}, y_{2}, z_{2}\right) and a plane Ax+By+Cz+D=0A x + B y+C z+D = 0 are given. Without finding its point of intersection with the line PQP Q, find the ratio in which this point divides the segment PQP Q.

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Problem 411

Two points P(x1,y1,z1)P\left(x_{1}, y_{1}, z_{1}\right) and Q(x2,y2,z2)Q\left(x_{2}, y_{2}, z_{2}\right) are given. Find in what ratio the point of intersection of the line PQP Q with the plane

{x=x0+α1u+α2vy=y0+β1u+β2vz=z0+γ1u+γ2v \begin{cases} x = x_{0}+\alpha _{1} u+\alpha _{2} v \\ y = y_{0}+\beta _{1} u+\beta _{2} v \\ z = z_{0}+\gamma _{1} u+\gamma _{2} v \end{cases}

divides the segment PQP Q.

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Problem 412

Prove that the vector with coordinates (A,B,C)(A, B, C) is always directed toward the "positive" half-space relative to the plane Ax+By+Cz+D=0A x+B y+C z+D = 0.

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Problem 413

A point (x0,y0,z0)\left(x_{0}, y_{0}, z_{0}\right) is given. Under what necessary and sufficient condition does this point lie between the two parallel planes Ax+By+Cz+D=0A x+B y+C z+D = 0 and Ax+By+Cz+E=0A x+B y+C z+E = 0?

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Problem 414

Find the necessary and sufficient condition for a point to lie inside the tetrahedron formed by the planes

A1x+B1y+C1z+D1=0,A2x+B2y+C2z+D2=0A3x+B3y+C3z+D3=0,A4x+B4y+C4z+D4=0 \begin{array}{ll} A_{1} x+B_{1} y+C_{1} z+D_{1} = 0, & A_{2} x+B_{2} y+C_{2} z+D_{2} = 0 \\ A_{3} x+B_{3} y+C_{3} z+D_{3} = 0, & A_{4} x+B_{4} y+C_{4} z+D_{4} = 0 \end{array}
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Problem 415

Four planes are given: x+y=0,x−z=0,x+y+2z=0x+y = 0, x-z = 0, x+y+2 z = 0, y=0y = 0. In each of the following cases, find planes passing through the point PP such that the quadrilaterals cut out on them by these planes are parallelograms, and determine whether the point PP lies inside or outside these parallelograms:

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(1)

P(2,−1,0)P(2,-1,0);

(2)

P(−1,3,2)P(-1,3,2).

Problem 416

Find the equation of the plane that passes through the point (2,3,−1)(2,3,-1) and is perpendicular to the vector (1,−3,−1)(1,-3,-1).

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Problem 417

Find the equation of the plane that passes through the point (1,1,1)(1,1,1) and is perpendicular to the line

x−12=y+23=z−3−2 \frac{x-1}{2} = \frac{y+2}{3} = \frac{z-3}{-2}
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Problem 418

Set up the equation of the plane passing through the point (x1,y1,z1)\left(x_{1}, y_{1}, z_{1}\right) and perpendicular to the line

x−x0a=y−y0b=z−z0c \frac{x-x_{0}}{a} = \frac{y-y_{0}}{b} = \frac{z-z_{0}}{c}
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Problem 419

Find the equation of the plane perpendicular to the line x+2y−z+5=0,3x+y+z−7=0x + 2 y-z+5 = 0,3 x+y+z-7 = 0 and passing through the point (2,−3,1)(2,-3,1).

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Problem 420

Find the equation of the plane that is perpendicular to the planes 2x+y−z+7=02 x+y-z+7 = 0 and x−3y+z−1=0x-3 y+z-1 = 0 and passes through the point (−1,1,0)(-1,1,0).

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Problem 421

Give a parametric description of the plane passing through the point (2,−1,1)(2,-1,1) and perpendicular to the line x−2y+z+3=0,2x+3y−z+8=0x-2 y+z+3 = 0,2 x+3 y-z+8 = 0.

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Problem 422

Find the equation of the plane perpendicular to the plane 4x+2y−z+8=04 x+2 y-z+8 = 0 and passing through the points (0,1,−2)(0,1,-2) and (2,−1,1)(2,-1,1).

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Problem 423

Set up the equation of the plane that passes through the points A(1,0,3)A(1,0,3) and B(2,−1,4)B(2,-1,4) perpendicular to the plane given by the parametric equations x=2u+4v,y=6v,z=3−u−vx = 2 u+4 v, y = 6 v, z = 3-u-v.

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Problem 424

In the pencil defined by the planes 3x−y+z−2=03 x-y+z-2 = 0 and x+y−6z−1=0x+y-6 z-1 = 0, find the planes that are perpendicular to the given ones.

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Problem 425

Set up the equations of the perpendiculars dropped from the point (1,−7,2)(1,-7,2) onto the coordinate axes OxO x and OyO y.

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Problem 426

Write the parametric equations of the perpendicular dropped from the point (x0,y0,z0)\left(x_{0}, y_{0}, z_{0}\right) onto the plane Ax+By+Cz+D=0A x+B y+C z+D = 0.

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Problem 427

Find the equation of the perpendicular dropped from the point P(1,−1,2)P(1,-1,2) onto the line

ℓ:x2=y−21=z+1−1 \ell : \frac{x}{2} = \frac{y-2}{1} = \frac{z+1}{-1}

and the distance from the point PP to the line ℓ\ell.

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Problem 428

Set up the equation of the perpendicular dropped from the point (x1,y1,z1)\left(x_{1}, y_{1}, z_{1}\right) onto the line

x−x0a=y−y0b=z−z0c \frac{x-x_{0}}{a} = \frac{y-y_{0}}{b} = \frac{z-z_{0}}{c}
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Problem 429

Find the distance from the point (1,3,5)(1,3,5) to the line

{2x+y+z−1=03x+y+2z−3=0 \begin{cases} 2 x+y+z-1 = 0 \\ 3 x+y+2 z-3 = 0 \end{cases}
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Problem 430

Find the distance from the point (1,−1,0)(1,-1,0) to the line x=2+tx = 2+t, y=−1−t,z=2ty = -1-t, z = 2 t.

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Problem 431

Find the point symmetric to the point (1,3,−4)(1,3,-4) with respect to the plane 3x+y−2z=03 x+y-2 z = 0.

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Problem 432

Find the point symmetric to the point (1,2,3)(1,2,3) with respect to the line

x−81=y−113=z−4−1 \frac{x-8}{1} = \frac{y-11}{3} = \frac{z-4}{-1}
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Problem 433

On the axis OzO z find the point equidistant from the point M(1,−2,0)M(1,-2,0) and the plane 3x−2y+6z−9=03 x-2 y+6 z-9 = 0.

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Problem 434

On the plane 5x−3y+7z+10=05 x-3 y+7 z+10 = 0 find a point such that the sum of the distances from it to the points (7,−1,5)(7,-1,5) and (29,3,−9)(29,3,-9) is smallest.

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Problem 435

The vertices of a tetrahedron P(1,0,0),Q(1,0,2),R(1,1,1)P(1,0,0), Q(1,0,2), R(1,1,1), S(3,0,0)S(3,0,0) are given. Compute the length of the altitude dropped from the vertex PP onto the plane of the face QRSQ R S.

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Problem 436

Set up the equation of the plane parallel to the plane x+3y−z+17=0x+3 y-z+17 = 0 and situated at a distance 11\sqrt{11} from the point (2,−1,1)(2,-1,1).

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Problem 437

Find the distance from the point (1,2,2)(1,2,2) to the plane given by the parametric equations x=2+3s+4t,y=5+6s+7tx = 2+3 s+4 t, y = 5+6 s+7 t, z=8+9s+10tz = 8+9 s+10 t.

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Problem 438

Find the distance between the planes 2x−4y−2z−1=02 x-4 y-2 z-1 = 0 and 3x−6y−3z+1=03 x-6 y-3 z+1 = 0.

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Problem 439

Find the distance between the planes Ax+By+Cz+D1=0A x+B y+C z+D_{1} = 0 and Ax+By+Cz+D2=0A x+B y+C z+D_{2} = 0.

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Problem 440

Find the angle between the planes 3x+4y−5z+1=03 x+4 y-5 z+1 = 0 and x+2y+2z−18=0x + 2 y+2 z-18 = 0.

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Problem 441

Set up the equations of the bisector planes of the dihedral angles between the planes:

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(1)

7x+y−6=0,3x+5y−4z+1=07 x+y-6 = 0, \quad 3 x+5 y-4 z+1 = 0;

(2)

x−2y+2z+3=0,4x+y−8z−1=0x-2 y+2 z+3 = 0,4 x+y-8 z-1 = 0.

Problem 442

Planes Π1:4x+y−8z−1=0\Pi_{1}: 4 x+y-8 z-1 = 0 and Π2:x−2y+2z+3=0\Pi_{2}: x-2 y+2 z + 3 = 0 are given. Find the equation of a plane Π3\Pi_{3} such that Π2\Pi_{2} bisects the dihedral angle between Π1\Pi_{1} and Π3\Pi_{3}.

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Problem 443

Find the necessary and sufficient conditions for the point (x0,y0,z0)(x_{0}, y_{0}, z_{0}) to lie in the acute angle formed by two intersecting, not mutually perpendicular planes

A1x+B1y+C1z+D1=0,A2x+B2y+C2z+D2=0 A_{1} x+B_{1} y+C_{1} z+D_{1} = 0, \quad A_{2} x+B_{2} y+C_{2} z+D_{2} = 0
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Problem 444

In which angle between the planes 7x+3y+z=0,3x+3y+z+2=07 x+3 y+z = 0,3 x+3 y + z+2 = 0 (acute or obtuse) does the point (1,−1,1)(1,-1,1) lie?

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Problem 445

Find the equation of the plane passing through the line of intersection of the planes x−y−z−1=0x-y-z-1 = 0 and 2x+10y−2z−5=02 x+10 y-2 z-5 = 0 and bisecting the acute angle between them.

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Problem 446

Find the equation of the plane passing through the line of intersection of the planes 5x−2y+2z−4=05 x-2 y+2 z-4 = 0 and 8x+2y−8z+3=08 x+2 y-8 z+3 = 0 and bisecting the angle between them in which the point (−1,−1,−1)(-1,-1,-1) lies.

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Problem 447

Write the equation of the bisector plane of the obtuse dihedral angle formed by the plane 2x−3y+6z−6=02 x-3 y+6 z-6 = 0 with the plane OyzO y z.

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Problem 448

Inside the triangle cut out on the plane OxyO x y by the planes x+4y+8z+8=0,x−2y+2z+2=0,3x+4y+12=0x+4 y+8 z+8 = 0, x-2 y+2 z+2 = 0,3 x+4 y+12 = 0, find the point equidistant from these planes.

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Problem 449

Find the center and radius of the sphere inscribed in the tetrahedron bounded by the coordinate planes and the plane 11x−10y−2z−57=011 x-10 y-2 z-57 = 0.

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Problem 450

Four planes forming a tetrahedron are given. How many spheres are there tangent to all of them?

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Problem 451

Find the angle between the lines

x1=y+1−1=z−1−1 and x−11=y1=z+11 \frac{x}{1} = \frac{y+1}{-1} = \frac{z-1}{-1} \quad \text{ and } \quad \frac{x-1}{1} = \frac{y}{1} = \frac{z+1}{1}
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Problem 452

Verify that the two lines x=1+2t,y=2t,z=tx = 1+2 t, y = 2 t, z = t and x=11+8t,y=6+4t,z=2+tx = 11+8 t, y = 6+4 t, z = 2+t intersect, and write the equations of the bisector of the obtuse angle between them.

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Problem 453

Find the angle between the plane OxyO x y and the line

x−10=y1=z−21 \frac{x-1}{0} = \frac{y}{1} = \frac{z-2}{1}
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Problem 454

Through the axis OzO z pass a plane forming an angle π/3\pi / 3 with the plane 2x+y−5z−7=02 x+y-\sqrt{5} z-7 = 0.

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Problem 455

The coordinate axes serve as the diagonals of a regular octahedron whose edges equal a2a \sqrt{2}. Find:

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(1)

the equations of the faces of the octahedron;

(2)

the dihedral angles;

(3)

the center and radius of the inscribed sphere.

Problem 456

In the pencil determined by the planes x+z−1=0x+z-1 = 0 and x+y−z+2=0x+y-z+2 = 0, find the plane forming an angle arccos⁡(1/10)\arccos (1 / \sqrt{10}) with the plane y+z+6=0y+z+6 = 0.

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Problem 457

Through the line

x1=y+1−1=z−10 \frac{x}{1} = \frac{y+1}{-1} = \frac{z-1}{0}

pass a plane such that the acute angle between its lines of intersection with the planes OxzO x z and OyzO y z equals π/3\pi / 3.

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Problem 458

It is known that the planes

Akx+Bky+Ckz+Dk=0,k=1,2,3 A_{k} x+B_{k} y+C_{k} z+D_{k} = 0, \quad k = 1,2,3

form a prism. Find the necessary and sufficient conditions for all three of its interior dihedral angles to be acute.

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Problem 459

Prove that the three planes x−2y+2z=0,2x−y−2z+2=0x-2 y+2 z = 0,2 x-y-2 z+2 = 0, 5x+2y−14z+14=05 x+2 y-14 z+14 = 0 form a prism. Find: the value γ\gamma of the interior dihedral angle of this prism formed by the first and second planes; the axis ℓ\ell and radius rr of the cylinder inscribed in the prism.

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Problem 460

Set up the equations of the orthogonal projection of the line

x−13=y+12=z−21 \frac{x-1}{3} = \frac{y+1}{2} = \frac{z-2}{1}

onto the plane 5x+6y−2z+1=05 x+6 y-2 z+1 = 0.

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Problem 461

Set up the equations of the common perpendicular to the two lines

x1=y+43=z2,x−32=y+2−3=z+3−2 \frac{x}{1} = \frac{y+4}{3} = \frac{z}{2}, \quad \frac{x-3}{2} = \frac{y+2}{-3} = \frac{z+3}{-2}
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Problem 462

Set up the equations of the common perpendicular to the two lines

x−18=y−24=z−31,{x+y=1x+2y+2z=−1 \frac{x-1}{8} = \frac{y-2}{4} = \frac{z-3}{1}, \quad \begin{cases} x+y = 1 \\ x+2 y+2 z = -1 \end{cases}

and find the distance dd between these lines. Find the points of intersection of the common perpendicular with these lines.

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Problem 463

Two lines are given: x−y+z+1=0,2x+3y−z+2=0x-y+z+1 = 0,2 x+3 y-z+2 = 0 and x=0x = 0, x+2y−z+1=0x+2 y-z+1 = 0. Find the distance between them and set up the equations of the common perpendicular.

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Problem 464

Find the distance between the lines

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(1)

x+y−1=0x+y-1 = 0, z=0z = 0 and x=1−t,y=−2+t,z=−1+3tx = 1-t, y = -2+t, z = -1+3 t;

(2)

x−11=y−22=z3\frac{x-1}{1} = \frac{y-2}{2} = \frac{z}{3} and {x+y−z+1=0,2x−y+3=0.\begin{cases} x+y-z+1 = 0, \\ 2 x-y+3 = 0. \end{cases}

Problem 465

To the nonintersecting diagonals of the faces of a cube that have a common edge, draw a common perpendicular. In what ratio do the points of intersection of the diagonals with their common perpendicular divide these diagonals?

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Problem 466

Find the distance between the diagonal of a cube and a diagonal of a face not intersecting it, if the edge of the cube equals 1.

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Problem 467

Find the distance dd from the point (x0,y0,z0)(x_{0}, y_{0}, z_{0}) to the plane Ax+By+Cz+D=0A x + B y+C z+D = 0, knowing the metric coefficients gijg_{i j} of the basis e1,e2,e3\mathbf{e}_{1}, \mathbf{e}_{2}, \mathbf{e}_{3}.

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Problem 468

Find the angles between the planes A1x+B1y+C1z+D1=0A_{1} x+B_{1} y+C_{1} z+D_{1} = 0, A2x+B2y+C2z+D2=0A_{2} x+B_{2} y+C_{2} z+D_{2} = 0, knowing the metric coefficients gijg_{i j} of the basis e1,e2,e3\mathbf{e}_{1}, \mathbf{e}_{2}, \mathbf{e}_{3}.

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Problem 469

Find the necessary and sufficient condition for perpendicularity of two planes A1x+B1y+C1z+D1=0,A2x+B2y+C2z+D2=0A_{1} x+B_{1} y+C_{1} z+D_{1} = 0, A_{2} x+B_{2} y+C_{2} z + D_{2} = 0, knowing the metric coefficients gijg_{i j} of the basis e1,e2,e3\mathbf{e}_{1}, \mathbf{e}_{2}, \mathbf{e}_{3}.

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Problem 470

Find the angle φ\varphi formed by the line

x−x0a=y−y0b=z−z0c \frac{x-x_{0}}{a} = \frac{y-y_{0}}{b} = \frac{z-z_{0}}{c}

with the plane Ax+By+Cz+D=0A x+B y+C z+D = 0, knowing the metric coefficients gijg_{i j} of the basis e1,e2,e3\mathbf{e}_{1}, \mathbf{e}_{2}, \mathbf{e}_{3}.

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Problem 471

Find the necessary and sufficient condition for perpendicularity of the line

x−x0a=y−y0b=z−z0c \frac{x-x_{0}}{a} = \frac{y-y_{0}}{b} = \frac{z-z_{0}}{c}

and the plane Ax+By+Cz+D=0A x+B y+C z+D = 0, knowing the metric coefficients gijg_{i j} of the basis e1,e2,e3\mathbf{e}_{1}, \mathbf{e}_{2}, \mathbf{e}_{3}.

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Problem 472

Find the volume VV of the tetrahedron ABCDA B C D given by its vertices A(x1,y1,z1),B(x2,y2,z2),C(x3,y3,z3),D(x4,y4,z4)A\left(x_{1}, y_{1}, z_{1}\right), B\left(x_{2}, y_{2}, z_{2}\right), C\left(x_{3}, y_{3}, z_{3}\right), D\left(x_{4}, y_{4}, z_{4}\right), knowing the metric coefficients gijg_{i j} of the basis e1,e2,e3\mathbf{e}_{1}, \mathbf{e}_{2}, \mathbf{e}_{3}.

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Problem 473

Knowing the metric coefficients gijg_{i j}, find the distance from the point (x0,y0,z0)(x_{0}, y_{0}, z_{0}) to the axis OzO z.

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