鱼钩
花朵
共回答了17个问题采纳率:88.2% 举报
这么简单都没人答.
1)积分[0,a] f(x)dx = 积分[0,a/2] f(x)dx + 积分[a/2,a] f(x)dx
2)设x=a-y,那么dx= - dy ,
积分[a/2,a] f(x)dx = 积分[a/2,0] f(a-y) (-dy) = 积分[0,a/2] f(a-y)dy =积分[a/2,a] f(y)dy
3)积分[0,a] f(x)dx = 积分[0,a/2] f(x)dx + 积分[a/2,a] f(y)dy =2倍积分[0,a/2] f(x)dx
1年前
5