Q. Use polar coordinates to find the volume of the given solid.above the cone z=x2+y2 and below the sphere x2+y2+z2=81
Write Equations: First, let's write the equations of the cone and the sphere in polar coordinates. For the cone, we have z=r (since z=x2+y2 and in polar coordinates, x=rcos(θ), y=rsin(θ), so x2+y2=r2). For the sphere, we have r2+z2=81.
Set Up Integral: Now, we'll set up the integral to find the volume. We need to integrate in the r and θ directions, as well as the z direction. The limits for θ are from 0 to 2π, since it's a full rotation around the z-axis. The limits for r will be from 0 to the intersection of the cone and sphere, and the limits for z will be from the cone (θ0) to the sphere (θ1).
Find Intersection: To find the intersection of the cone and sphere, we set their equations equal: r=81−r2. Squaring both sides, we get r2=81−r2, which simplifies to 2r2=81, so r2=40.5, and r=40.5.
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