∫(pai/2到0)sinx/8+sin^2x dx
问题描述:
∫(pai/2到0)sinx/8+sin^2x dx
答
∫(π/2到0)[sinx/(8+sin²x)] dx
=-∫(0,π/2)dcosx/(9-cos²x)
=-∫(0,π/2)dcosx/(3+cosx)(3-cosx)
=(-1/6)∫(0,π/2)[1/(3+cosx)+1/(3-cosx)]dcosx
=(-1/6)[ln(3+cosx)-ln(3-cosx)]|(0,π/2)
=(-1/6)×[(ln3-ln3)-(ln4-ln2)]
=(1/6)×ln2
=(ln2)/6不好意思题目是0到pai/2我打错了。。而且分母是x^2嗯,我就是按这个做的