设f(x)连续,证明:∫0x[∫0tf(u)du]dt=∫0xf(t)(x一t)dt.

admin2016-09-30  29

问题 设f(x)连续,证明:∫0x[∫0tf(u)du]dt=∫0xf(t)(x一t)dt.

选项

答案令F(x)=∫0xf(t)dt,则F’(x)=f(x),于是∫0x[∫0tf(u)du]dt=∫0xF(t)dt,∫0xf(t)(x—t)dt=x∫0xf(t)dt一∫0xtf(t)dt=xF(x)一∫0xtdF(t) =xF(x)一tF(t)|0x+∫0xF(t)dt=∫0xF(t)dt. 命题得证.

解析
转载请注明原文地址:https://kaotiyun.com/show/szu4777K
0

最新回复(0)