Use a plane to cut a cone and a sphere. What are the shapes of the cross sections?

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1. As shown in the figure, the cross-section of a plane passing through the apex of a cone is () A. B. C. D.
2. If a cone is cut by a plane, can the cross section be a triangle? A right triangle? When the cross section is a circle
3. When the plane is cut perpendicular to the cone axis, the shape of the intersection line is (); when the plane is cut parallel to the cone axis, the shape of the intersection line is () When the plane cuts perpendicular to the cone axis, the shape of the intersection line is (); when the plane cuts parallel to the cone axis, the shape of the intersection line is (); when the plane cuts through the cone vertex, the shape of the intersection line is ()
4. The section plane intersects with the axis of the cone A. Circle B. Intersect two lines C. Ellipse
5. If the plane of the plane section is perpendicular to the axis of the cone, what is the intersection line?
6. When the plane parallel to the bottom of the cone is used to cut the cone, the ratio of the area of the cross section to the area of the bottom is 1:3. The ratio of the two sections which divide the generatrix of the cone into two sections is () A. 1：3B. 1：（3-1）C. 1：9D. 3：2
7. Can the cross section area of a cone cut by a plane be exactly half of the area of the bottom circle
8. If the cone is cut into two parts with equal side area by a plane parallel to the bottom, and the volume of the small cone is 1, then the volume of the original cone is ()
9. If a plane parallel to the ground of the cone divides the cone into two equal segments, then the ratio of the side area of the two parts is I did a good job Can you do me a favor
10. A plane parallel to the bottom of a cone cuts the cone, the diameter of the cross section and the bottom is 3cm and 9cm respectively, and the distance between the cross section and the bottom is 4cm Find the area of this cone's axis section
11. The shape of the cross section of a plane passing through the apex of a cone may be
12. Use a plane to cut off a cylinder and a cone. The shape of the section is the same ()
13. Is it possible to cut a conic section with a plane
14. The surface integral ∫ ∫ xdydz + y ^ 2dzdy + zdxdy, ∑ is the upper side of the triangle on the plane where x + y + Z = 1 is cut by the coordinate plane
15. ∫ (x ^ 2-y ^ 2) dydz + (y ^ 2-z ^ 2) dzdx + (Z ^ 2-x ^ 2) DXDY how to use Gauss formula? S is the upper half ellipsoid x ^ 2 / A ^ 2 + y ^ 2 / b ^ 2 + Z ^ 2 = 1 (z > = 0), take the upper side, and the Gauss formula is ∫ ∫ (x + y + Z) DV, which will not be done later
16. The surface integral ∫ (y ^ 2-x) dydz + (Z ^ 2-y) dzdx + (x ^ 2-z) DXDY, ∑ is Z = 1-x ^ 2-y ^ 2, which is located on the upper side above the side
17. Surface integral ∫ ∫ xdydz + Z ^ 2dxdy / (x ^ 2 + y ^ 2 + Z ^ 2), where surface ∑ is surrounded by x ^ 2 + y ^ 2 = R ^ 2 and z = R, z = - R
18. Using Gauss formula, we can find the surface fraction ∮ XY ^ 2dydz + YZ ^ 2dzdx + ZX ^ 2dxdy, where ∑ is the outside of the sphere x ^ 2 + y ^ 2 + Z ^ 2 = R ^ 2 The reference answer is 4 π R ^ 5 / 5. But I'm always 2 π R ^ 5 / 5 My score is settled on the spot. My adoption rate is 100% Let P = XY & # 178;, q = YZ & # 178;, r = ZX & # 178; ∵αP/αx=y²,αQ/αy=z²,αR/αz=x² The original formula = ∫ ∫ (α P / α x + α Q / α y + α R / α z) dxdydz is obtained from Gauss formula =∫∫∫(x²+y²+z²)dxdydz =∫dθ∫sinφdφ∫r^4dr =(2π)[0--(1)](R^5/5-0) =2πR^5/5
19. Let the tangent plane of the point (x, y, z) on the surface ∑: x ^ 2 / A ^ 2 + y ^ 2 / b ^ 2 + Z ^ 2 / C ^ 2 = 1 be π, and calculate the surface integral ∫ ∫ ∑ 1 / λ DS, where λ is the distance from the coordinate origin to π
20. The domain of surface integral (x ^ 2 + y ^ 2) DS is bounded by z = x ^ 2 + y ^ 2 and z = 1 The answer is (5 radical 5 + 6) / 12 seeking process or seeking correct answer (the answer may be wrong)