1/(x+x3)在积分区间为[1,x3是x的立方的意思

1/(x+x3)在积分区间为[1,x3是x的立方的意思
1/(x+x3)在积分区间为[1,
x3是x的立方的意思

1/(x+x3)在积分区间为[1,x3是x的立方的意思
可以这样想啊
1/(x+x^3)=（x^2+1）/(x+x^3)-x^2/(x+x^3)=1/x-x/(x^2+1)
∫1/(x+x^3)dx=Inx-1/2∫1/(x^2+1)d(x^2+1)
=Inx-1/2In(x^2+1)
取[1,2]时,原式＝In2-In1-1/2(In5-In2)
=3/2In2-1/2In5
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