解答题 18.设L:
【正确答案】(1)所求的面积为
A=∫02πaydx=∫0a(1一cost).a(1一cost)dt=a20(1一cost)2dt=
=8a20πsin4t dt=
(2)所求体积为
V=π∫02πdy2dx=π∫0a2(1一cost)2.a(1一cost)dt
==16πa30πsin6tdt=
【答案解析】