Osculating plane of a space curve

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Find the osculating plane of the curve

y2=x,x2=z y^{2} = x, \qquad x^{2} = z

at the point (1,1,1)(1,1,1).

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Find the osculating plane of the curve

y=φ(x),z=aφ(x)+b. y = \varphi (x), \qquad z = a\varphi (x)+b .
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Find the osculating plane of the curve

x2=2az,y2=2bz. x^{2} = 2az, \qquad y^{2} = 2bz .
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Find the osculating plane of the curve x=etx=e^{t}, y=e−ty=e^{-t}, z=t2z=t\sqrt{2}.

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Find the osculating plane of the curve x=acos⁡tx=a\cos t, y=asin⁡ty=a\sin t, z=btz=bt.

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Find the osculating plane of the curve x=at2+bt+cx=at^{2}+bt+c, y=a1t2+b1t+c1y=a_{1}t^{2}+b_{1}t+c_{1}, z=a2t2+b2t+c2z=a_{2}t^{2}+b_{2}t+c_{2}.

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Prove that the osculating plane of the curve

x2=φ′(t),y2=t2φ′(t),z=φ(t), x^{2} = \varphi '(t), \qquad y^{2} = t^{2}\varphi '(t), \qquad z = \varphi (t),

lying on the conoidal surface z=φ(yx)z=\varphi \left(\dfrac {y}{x}\right), coincides with the tangent plane to this surface.

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Write the equations of the osculating, normal, and rectifying planes at an arbitrary point of the curve:

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(1)

the helix x=acos⁡t,y=asin⁡t,z=btx = a \cos t, y = a \sin t, z = b t;

(2)

x=t,y=t2,z=t3x = t, y = t^{2}, z = t^{3};

(3)

x=et,y=e−t,z=t2x = e^{t}, y = e^{-t}, z = t \sqrt{2};

(4)

x=etcos⁡t,y=etsin⁡t,z=etx = e^{t} \cos t, y = e^{t} \sin t, z = e^{t};

(5)

y2=x,x2=zy^{2} = x, x^{2} = z;

(6)

y=φ(x),z=aφ(x)+by = \varphi (x), z = a \varphi (x)+b.

Prove that the line drawn from an arbitrary point MM of the curve x=t,y=t2,z=t3x = t, y = t^{2}, z = t^{3} parallel to the plane z=0z = 0 until it meets the zz-axis lies in the osculating plane of the curve at the point MM.

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Write the equation of the osculating plane of the curve x=acos⁡t,y=bsin⁡t,z=etx = a \cos t, y = b \sin t, z = e^{t} at t=0t = 0.

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Write the equation of the osculating plane at the point (2;1;2)(2 ; 1 ; 2) of the curve that is the intersection of the sphere x2+y2+z2=9x^{2}+y^{2}+z^{2} = 9 and the hyperbolic cylinder x2−y2=3x^{2}-y^{2} = 3.

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Let Γ={M(t);a⩽t⩽b}\Gamma = \left\{ M(t) ; a \leqslant t \leqslant b\right\} be a twice continuously differentiable curve without singular points, t0∈[a;b],t0+Δt1∈[a;b]t_{0} \in [a ; b], t_{0}+\Delta t_{1} \in [a ; b] and t0+Δt2∈[a;b]t_{0} + \Delta t_{2} \in [a ; b]. Draw a plane through the points M(t0),M(t0+Δt1)M\left(t_{0}\right), M\left(t_{0}+\Delta t_{1}\right) and M(t0+Δt2)M\left(t_{0}+\Delta t_{2}\right). Prove that if at the point M(t0)M\left(t_{0}\right) the curvature is nonzero, then as Δt1→0\Delta t_{1} \rightarrow 0 and Δt2→0\Delta t_{2} \rightarrow 0 this plane tends (define this notion) to the osculating plane at the point M(t0)M\left(t_{0}\right).

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Let π\pi be the plane passing through the tangent line at the point M(s0)M\left(s_{0}\right) of a twice continuously differentiable curve Γ={M(s);0⩽s⩽S}\Gamma = \left\{ M(s) ; 0 \leqslant s \leqslant S\right\}, where ss is the variable arc length of the curve Γ,s0∈[0,S]\Gamma , s_{0} \in [0, S], and let d(Δs)d(\Delta s) be the distance from the point M(s0+Δs)M\left(s_{0}+\Delta s\right) to the plane π\pi.

Prove that the plane π\pi is the osculating plane of the curve Γ\Gamma if and only if

lim⁡Δs→0d(Δs)Δs2=0 \lim _{\Delta s \rightarrow 0} \frac{d(\Delta s)}{\Delta s^{2}} = 0
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References

[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. Предел. Непрерывность. Дифференцируемость. 2-е изд., ФИЗМАТЛИТ, 2003.