求不定积分∫dx(1+ex)2.-数学

题目简介

求不定积分∫dx(1+ex)2.-数学

题目详情

求不定积分
dx
(1+ex )2
题型:解答题难度:中档来源:江苏

答案

令1+ex=t,
则dt=exdx=(t-1)dx,dx=class="stub"dt
t-1
.

∫class="stub"dx
(1+ex)2
=∫class="stub"dt
(t-1)t2

=∫(class="stub"1
t(t-1)
-class="stub"1
t2
)dt

=∫(class="stub"1
t-1
-class="stub"1
t
-class="stub"1
t2
)dt

=ln(t-1)-lnt+class="stub"1
t
+C

=lnex-ln(1+ex)+class="stub"1
1+ex
+C

=x-ln(1+ex)+class="stub"1
1+ex
+C

更多内容推荐