Using double in tegrals to find the area/volume

[zhuyilun]

Homework Statement

1. r=4+3*cos($$\theta$$)
2.bounded by the cylinders x^2+y^2=r^2 and y^2+z^2=r^2
3. the solid enclosed by the parabolic cylinder y=x^2 and the planes z=3y and z=2+y

Homework Equations

The Attempt at a Solution

1. i set up the double integral of r and with r= o to 4+3*cos($$\theta$$), $$\theta$$=0 to 2 pi
2. i set up the double integral of (r^2-y^2)^(1/2) and with x=-(r^2-y^2)^(1/2) to x= (r^2-y^2)^(1/2), y= -r to y=r. and muliply the volume by two due to the symmetricity of the graph
3. i know i should find the volume of one and subtract the volume of the second one. but that's all i know. i don't know how to set up the integrals

can anyone tell me what i did in 1 and 2 is right or not and help me w/ 3? thx