Name T GE uus keep FERNANDEZ Math 27303 written Assignment 1
Solution
in cylindrical coordinates :x=rcos, y=rsin,x2+y2=r2
x2+y2+z2=9
=>r2+z2=9
=>z=-(9-r2),z=(9-r2)
on xy plane, z=0
=>r2+02=9
=>r =3
x2+y2=4=22
=>r=2
02,2r3 ,-(9-r2)z(9-r2)
dv =r dz dr d
volume of required solid =[0 to 2] [2 to 3] [-(9-r2) to (9-r2)] r dz dr d
volume of required solid =[0 to 2] [2 to 3][-(9-r2) to (9-r2)] r z dr d
volume of required solid =[0 to 2] [2 to 3]r ((9-r2) -(-(9-r2))) dr d
volume of required solid =[0 to 2] [2 to 3]2r(9-r2) dr d
volume of required solid =[0 to 2][2 to 3](-2/3)(9-r2)3/2 d
volume of required solid =[0 to 2](-2/3)[(9-32)3/2 -(9-22)3/2 ] d
volume of required solid =[0 to 2](-2/3)[0 -53/2 ] d
volume of required solid =[0 to 2](2/3)53/2 d
volume of required solid =[0 to 2](2/3)53/2
volume of required solid = (2/3)53/2 (2 -0)
volume of required solid = (205 )/3 46.832 cubic units
