cotarou
花朵
共回答了14个问题采纳率:100% 举报
1、∫cosxdx/sin²x=∫cscxcotxdx=-cscx + c
2、∫sec5xdx=(1/5)∫sec5xd(5x)=(1/5)ln|sec5x+tan5x| + c
3、∫dx/[x^(1/2)+x^(1/3)],u=x^1/6,x=u^6,dx=6u^5du
= 6∫u^5du/(u³+u²)
= 6∫u³du/(u+1)
= 6∫[u²-u-1/(u+1)+1]du
= 6[u³-u²-ln|u+1|+u] + c
= 2x^(1/2)-3x^(1/3)+6x^(1/6)-6ln|1+x^(1/6)| + c
4、∫√(x-1)dx / x,u=√(x-1),du=dx/[2√(x-1)]
= 2∫u²du/(1+u²)
= 2∫[1-1/(1+u²)]du
= 2(u-arctanu) + c
= 2√(x-1) - 2arctan√(x-1) + c
5、∫sin√xdx
= ∫ (2√x)sin√xdx / (2√x)
= 2∫√xsin√xd√x
= -2∫√xdcos√x
= - 2√xcos√x + 2∫cos√xd√x
= 2sin(√x) - 2(√x)cos(√x) + c
1年前
1