用电脑拍的,有点不清楚.
来源:学生作业帮 编辑:搜搜做题作业网作业帮 分类:数学作业 时间:2024/07/25 13:54:11
用电脑拍的,有点不清楚.
[S_{t:0->x}(x-t)f(t)dt]' = [xS_{t:0->x}f(t)dt - S_{t:0->x}tf(t)dt]'
= S_{t:0->x}f(t)dt + x[S_{t:0->x}f(t)dt]' - [S_{t:0->x}tf(t)dt]'
= S_{t:0->x}f(t)dt + xf(x) - xf(x)
= S_{t:0->x}f(t)dt
= S_{t:0->x}f(t)dt + x[S_{t:0->x}f(t)dt]' - [S_{t:0->x}tf(t)dt]'
= S_{t:0->x}f(t)dt + xf(x) - xf(x)
= S_{t:0->x}f(t)dt