求不定积分(高数上册总习题四27题)

2025-01-24 08:47:10
推荐回答(2个)
回答1:

∫ (x+sinx)/(1+cosx)dx
=∫x/(1+cosX)dx+∫sinx/(1+cosx)dx
=∫xsec^2(x/2)d(x/2)-∫1/(1+cosx)d(1+cosx)
=∫xd[tan(x/2)]-ln(1+cosx) (分部积分)
=xtan(x/2)-∫tan(x/2)dx-ln(1+cosx)
=xtan(x/2)+2ln∣cos(x/2)∣-ln2-ln∣cos(x/2)∣+C1
=xtan(x/2)+C

回答2:

sinx=2sin(x/2)cos(x/2),1+cosx=2(cos(x/2))^2
∫ (x+sinx)/(1+cosx)dx
=∫x×1/2×(sec(x/2))^2dx+∫tan(x/2)dx
=∫xd(tan(x/2))+∫tan(x/2)dx 前者分部积分
=xtan(x/2)-∫tan(x/2)dx+∫tan(x/2)dx
=x×tan(x/2)+C