Volume by cross-sectional areas

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Find the volume of a hip roof, whose base is a rectangle with side lengths aa and bb, whose ridge has length cc, and whose height is hh.

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Find the volume of a truncated wedge whose parallel top and bottom faces are rectangles with side lengths AA, BB and aa, bb respectively, and whose height equals hh.

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Find the volume of a truncated cone (frustum) whose top and bottom faces are ellipses with semi-axes AA, BB and aa, bb respectively, and whose height equals hh.

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A solid is the set of points M(x,y,z)M(x,y,z) such that 0⩽z⩽10\leqslant z\leqslant 1, and moreover, if zz is rational, 0⩽x⩽10\leqslant x\leqslant 1, 0⩽y⩽10\leqslant y\leqslant 1; while if zz is irrational, −1⩽x⩽0-1\leqslant x\leqslant 0, −1⩽y⩽0-1\leqslant y\leqslant 0. Prove that although the corresponding integral is

∫01S(z)dz=1, \int _{0}^{1}S(z) dz=1 ,

the volume of this solid does not exist.

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Find the volume enclosed by the following surfaces:

x2a2+y2b2=1,z=−cax,z=0. \dfrac {x^{2}}{a^{2}}+\dfrac {y^{2}}{b^{2}}=1 ,\quad z=-\dfrac {c}{a}x ,\quad z=0 .
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Find the volume enclosed by the following surfaces:

x2a2+y2b2+z2c2=1(ellipsoid). \dfrac {x^{2}}{a^{2}}+\dfrac {y^{2}}{b^{2}}+\dfrac {z^{2}}{c^{2}}=1\quad (\text{ellipsoid}) .
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Find the volume enclosed by the following surfaces:

x2a2+y2b2−z2c2=1,z=±c. \dfrac {x^{2}}{a^{2}}+\dfrac {y^{2}}{b^{2}}-\dfrac {z^{2}}{c^{2}}=1 ,\quad z=\pm c .
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Find the volume enclosed by the following surfaces:

x2+z2=a2,y2+z2=a2. x^{2}+z^{2}=a^{2} ,\quad y^{2}+z^{2}=a^{2} .
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Find the volume enclosed by the following surfaces:

x2+y2+z2=a2,x2+y2=ax. x^{2}+y^{2}+z^{2}=a^{2} ,\quad x^{2}+y^{2}=ax .
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Find the volume enclosed by the following surfaces:

z2=b(a−x),x2+y2=ax. z^{2}=b(a-x) ,\quad x^{2}+y^{2}=ax .
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Find the volume enclosed by the following surfaces:

x2a2+y2z2=1(0<z<a). \dfrac {x^{2}}{a^{2}}+\dfrac {y^{2}}{z^{2}}=1\quad (0<z<a) .
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Find the volume enclosed by the following surfaces:

x+y+z2=1,x=0,y=0,z=0. x+y+z^{2}=1 ,\quad x=0 ,\quad y=0 ,\quad z=0 .
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Find the volume enclosed by the following surface:

x2+y2+z2+xy+yz+zx=a2. x^{2}+y^{2}+z^{2}+xy+yz+zx=a^{2} .
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Liquid spills over the edge of a vessel in the shape of a cylinder with radius aa and height hh. Prove that at the moment when half of the bottom becomes exposed, the volume of the remaining liquid equals 23a2h\frac{2}{3}a^{2}h. (Archimedes.)

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Find the volume of the solid bounded by the surfaces z2+y2=1z^{2}+y^{2}=1, x2+z2=1x^{2}+z^{2}=1, by considering horizontal cross-sections.

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Find the volume of the solid bounded by the surfaces x2+y2=axx^{2}+y^{2}=ax, x−z=0x-z=0, x+z=0x+z=0, by considering cross-sections perpendicular to OxOx.

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Find the volume of the solid bounded by the surfaces x2+4y2=8zx^{2}+4y^{2}=8z, x2+4y2=1x^{2}+4y^{2}=1, z=0z=0.

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Find the volume of the solid bounded by the surfaces y2=2p(a−x)y^{2}=2p(a-x), x−z=0x-z=0, x−2z=0x-2z=0.

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Find the volume of the solid bounded by the surfaces z2=(a−x−y)az^{2}=(a-x-y)a; x=0x=0, y=0y=0, z=0z=0.

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Find the volume of the solid bounded by the surfaces z2=b(a−x)z^{2}=b(a-x), x2+y2=axx^{2}+y^{2}=ax.

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Find the volume of the solid bounded by the surfaces z=0z=0, by=x(a−z)by=x(a-z), by=−x(a−z)by=-x(a-z), x=bx=b.

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Find the volume of the solid bounded by the surfaces y2+z2=a2ch⁡2xay^{2}+z^{2}=a^{2}\ch^{2}\frac{x}{a}, −b<x<b-b<x<b.

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Water is poured into a right circular cylinder (a glass) of radius rr. The axis is tilted at an angle α\alpha to the horizontal. Part of the bottom — a segment with central angle 2φ2\varphi — is covered by water. Find the volume of the water.

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A right circular cone is cut into two parts by a plane passing through the center of the base and parallel to a generator. Find the volumes of the parts of the cone, given that the cross-sections of the cone by planes parallel to the generator are parabolic segments.

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A quarter of a right circular cylinder is cut by an inclined plane passing through a radius of the upper base and the endpoint of the radius of the lower base perpendicular to the first radius. Through the axis of the cylinder a plane is drawn at an angle φ\varphi to the aforementioned radius of the upper base. Find the volumes of the four parts of the quarter-cylinder.

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Find the volume bounded by the surface of the conoid a2l2y2=b2x2(a2−z2)a^{2}l^{2}y^{2}=b^{2}x^{2}(a^{2}-z^{2}) and the plane x=lx=l.

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Three mutually perpendicular lines passing through a single point are the axes of three circular cylinders of the same radius rr. Determine the volume of the solid lying inside all of them.

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The axes of two circular cylinders of radius rr intersect at an angle 2α2\alpha. Determine the volume of the solid bounded by these cylinders.

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Find the volume of the solid bounded by the surfaces.

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(1)

x2a2+y2b2=1,∣z∣=H\frac{x^{2}}{a^{2}}+\frac{y^{2}}{b^{2}} = 1,\left|z\right| = H;

(2)

x2a2+y2b2=(z−H)2H2,z=0\frac{x^{2}}{a^{2}}+\frac{y^{2}}{b^{2}} = \frac{(z-H)^{2}}{H^{2}}, z = 0;

(3)

2zc=x2a2+y2b2,z=H2 \frac{z}{c} = \frac{x^{2}}{a^{2}}+\frac{y^{2}}{b^{2}}, z = H;

(4)

x2a2+y2b2+z2c2=1\frac{x^{2}}{a^{2}}+\frac{y^{2}}{b^{2}}+\frac{z^{2}}{c^{2}} = 1;

(5)

x2a2+y2b2−z2c2=1,∣z∣=H\frac{x^{2}}{a^{2}}+\frac{y^{2}}{b^{2}}-\frac{z^{2}}{c^{2}} = 1,\left|z\right| = H

(6)

x2a2+y2b2−z2c2=−1,z=c+H\frac{x^{2}}{a^{2}}+\frac{y^{2}}{b^{2}}-\frac{z^{2}}{c^{2}} = -1, z = c+H.

Find the volume of the solid bounded by the surfaces.

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(1)

y2a2+x+za=1,x=0,y=0,z=0\frac{y^{2}}{a^{2}}+\frac{x+z}{a} = 1, x = 0, y = 0, z = 0;

(2)

x2+y2+z2+xy+yz+zx=a2x^{2}+y^{2}+z^{2}+x y+y z+z x = a^{2}

(3)

y2+z2=a2ch⁡2(x/a),∣x∣=by^{2}+z^{2} = a^{2} \operatorname {ch}^{2}(x / a),\left|x\right| = b;

(4)

a2(z2−y2)=x2z2,z=aa^{2}\left(z^{2}-y^{2}\right) = x^{2} z^{2}, z = a;

(5)

x2(z+a)2+y2(z−a)2=1\frac{x^{2}}{(z+a)^{2}}+\frac{y^{2}}{(z-a)^{2}} = 1;

(6)

(1−x2a2)(1−zc)2=y2b2,z=0\left(1-\frac{x^{2}}{a^{2}}\right)\left(1-\frac{z}{c}\right)^{2} = \frac{y^{2}}{b^{2}}, z = 0;

(7)

4a2x2(1−y2b2)=(x2+z2)24 a^{2} x^{2}\left(1-\frac{y^{2}}{b^{2}}\right) = \left(x^{2}+z^{2}\right)^{2}.

Find the volume of the solid bounded by the surfaces.

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(1)

x2a2+y2b2=1,zH=xa,z=0\frac{x^{2}}{a^{2}}+\frac{y^{2}}{b^{2}} = 1, \frac{z}{H} = \frac{x}{a}, z = 0;

(2)

z2=a(a−y),x=k1y,x=k2y,k2>k1z^{2} = a(a-y), x = k_{1} y, x = k_{2} y, k_{2} > k_{1};

(3)

xa=y2b2,xa+zc=1,xa−zc=1\frac{x}{a} = \frac{y^{2}}{b^{2}}, \frac{x}{a}+\frac{z}{c} = 1, \frac{x}{a}-\frac{z}{c} = 1;

(4)

x2a2+z2c2=1,yb−zc=0,yb+zc=0(z⩾0)\frac{x^{2}}{a^{2}}+\frac{z^{2}}{c^{2}} = 1, \frac{y}{b}-\frac{z}{c} = 0, \frac{y}{b}+\frac{z}{c} = 0(z \geqslant 0);

(5)

x2a2+y2b2=(z−H)2H2,zH=yb,z=0(y⩾0)\frac{x^{2}}{a^{2}}+\frac{y^{2}}{b^{2}} = \frac{(z-H)^{2}}{H^{2}}, \frac{z}{H} = \frac{y}{b}, z = 0(y \geqslant 0);

(6)

x2+y2=ax,∣x∣=∣z∣x^{2}+y^{2} = a x,\left|x\right| = \left|z\right|.

The base of a cone is a plane figure of area SS, the vertex of the cone is at distance HH from the plane of the base. Find the volume of the cone.

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The radius of a right circular cylinder equals rr. A plane, making an angle α\alpha with the axis of the cylinder, intersects its lateral surface and lower base, cutting off from this base a segment with central angle 2φ2 \varphi. Find the volume of the part of the cylinder bounded by this segment, the cutting plane, and the lateral surface of the cylinder.

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The opening angle of a right circular cone equals 2α(2α<π/2)2 \alpha (2 \alpha < \pi / 2). A plane perpendicular to a generator of the cone intersects it at a point at distance aa from the vertex. Find the volume of the part of the cone cut off.

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Through the center of the base of a right circular cone with radius rr and height hh a plane parallel to a generator of the cone is drawn. Find the ratio of the volumes of the parts into which the cone is divided.

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Find the volume of the solid bounded by the surfaces:

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(1)

x2a2+z2c2=1,y2b2+z2c2=1\frac{x^{2}}{a^{2}}+\frac{z^{2}}{c^{2}} = 1, \frac{y^{2}}{b^{2}}+\frac{z^{2}}{c^{2}} = 1;

(2)

x2=b(a−y),y2+z2=ayx^{2} = b(a-y), y^{2}+z^{2} = a y;

(3)

zc=x2a2+y2b2,z2c2=x2a2+y2b2\frac{z}{c} = \frac{x^{2}}{a^{2}}+\frac{y^{2}}{b^{2}}, \frac{z^{2}}{c^{2}} = \frac{x^{2}}{a^{2}}+\frac{y^{2}}{b^{2}};

(4)

by=x(a−z)b y = x(a-z), by =x(z−a),z=0,x=b= x(z-a), z = 0, x = b;

(5)

x2a2+y2b2+z2c2=1,5z6cx2a2+y2b2\frac{x^{2}}{a^{2}}+\frac{y^{2}}{b^{2}}+\frac{z^{2}}{c^{2}} = 1, \frac{5 z}{6 c} \frac{x^{2}}{a^{2}}+\frac{y^{2}}{b^{2}};

(6)

x24+y29+z216=1,x22−y236+z28=1\frac{x^{2}}{4}+\frac{y^{2}}{9}+\frac{z^{2}}{16} = 1, \frac{x^{2}}{2}-\frac{y^{2}}{36}+\frac{z^{2}}{8} = 1;

(7)

x2−4y23−z227=−1,x2−4y25−z245=1x^{2}-\frac{4 y^{2}}{3}-\frac{z^{2}}{27} = -1, x^{2}-\frac{4 y^{2}}{5}-\frac{z^{2}}{45} = 1.

The axes of an ellipse have lengths 2a2 a and 2b2 b. On every chord of the ellipse parallel to the axis of length 2a2 a, a square is constructed as on a diagonal, in the plane perpendicular to the other axis of the ellipse. Find the volume of the resulting solid.

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Two faces of a hexahedron are rectangles, the sides of one of them of lengths a1a_{1} and b1b_{1} being parallel to the sides of the other of lengths a2a_{2} and b2b_{2} respectively. The distance between the planes of these rectangles equals hh. Find the volume of the hexahedron.

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The volume of the triangular prism ABCA1B1C1A B C A_{1} B_{1} C_{1} equals VV. Consider all triangles lying in planes parallel to the bases, with vertices on the diagonals AB1,BC1A B_{1}, B C_{1} and CA1C A_{1} of the lateral faces of the prism. Find the volume of the solid formed by these triangles.

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A solid, having a certain volume, is located between the planes z=0z = 0 and z=hz = h. It is known that the area of the cross-section of the solid by the plane z=z = const is a function of the form S(z)=az2+bz+c,0⩽z⩽hS(z) = a z^{2}+b z+c, 0 \leqslant z \leqslant h. Prove that the volume of the solid equals

V=h6(S(0)+4Sh2+S(h)) V = \frac{h}{6}\left(S(0)+4 S \frac{h}{2}+S(h)\right)
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The axes of two circular cylinders, each of which has radius rr, intersect at an angle α\alpha. Find the volume of the solid bounded by these cylinders.

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On a circle x2+y2⩽r2x^{2}+y^{2} \leqslant r^{2}, as on a common base, two oblique cylinders are constructed. Their axes lie in the plane OyzO y z, and each makes an angle α\alpha with the axis OzO z. Find the volume of the solid bounded by the given circle and these cylinders.

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The axes of three cylinders (each of radius rr) are mutually perpendicular and intersect at one point. Find the volume of the solid bounded by these three cylinders.

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On the lateral surface of the cylinder x2+y2⩽R2,0⩽z⩽Hx^{2}+y^{2} \leqslant R^{2}, 0 \leqslant z \leqslant H lies a helix x=Rcos⁡2πα,y=Rsin⁡2πα,z=Hαx = R \cos 2 \pi \alpha , y = R \sin 2 \pi \alpha , z = H \alpha, 0⩽α⩽10 \leqslant \alpha \leqslant 1. A helical surface is formed by the perpendiculars dropped from the points of the helix onto the axis OzO z. Find the volume of the lower part of the cylinder bounded by this surface and the rectangle 0⩽x⩽R,0⩽z⩽H0 \leqslant x \leqslant R, 0 \leqslant z \leqslant H in the plane OxzO x z.

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On the lateral surface of the cone

x2+y2⩽R2,0⩽z⩽HR(R−x2+y2) x^{2}+y^{2} \leqslant R^{2}, \quad 0 \leqslant z \leqslant \frac{H}{R}\left(R-\sqrt{x^{2}+y^{2}}\right)

lies a conical helix

x=R(1−α)cos⁡2πα,y=R(1−α)sin⁡2πα,z=Hα,0⩽α⩽1 x = R(1-\alpha ) \cos 2 \pi \alpha , \quad y = R(1-\alpha ) \sin 2 \pi \alpha , \quad z = H \alpha , \quad 0 \leqslant \alpha \leqslant 1

A conical helical surface is formed by the perpendiculars dropped from the points of a helix onto the axis OzO z. To it is added a triangle with vertices (0;0;0),(0;0;H),(R;0;0)(0 ; 0 ; 0),(0 ; 0 ; H),(R ; 0 ; 0). Find the ratio of the volumes of the parts into which the resulting surface divides the cone.

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References

[Dem97] Demidovich B.P. Сборник задач и упражнений по математическому анализу. 13-е изд., Издательство Московского университета / Издательство "ЧеРо", 1997.
[ГюКу03] Гюнтер Н.М., Кузьмин Р.О. Сборник задач по высшей математике. 13-е изд., Издательство «Лань», 2003.
[ККЧ+03] Кудрявцев Л.Д., Кутасов А.Д., Чехлов В.И., Шабунин М.И. Интегралы. Ряды. 2-е изд., ФИЗМАТЛИТ, 2003.