∫arctan根号(x)/根号(x)*(1+x)令t=根号x x=t^2∫arctan t/t(1+t^2)dt^2怎么继续做?

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∫arctan根号(x)/根号(x)*(1+x)令t=根号x x=t^2∫arctan t/t(1+t^2)dt^2怎么继续做?

∫arctan根号(x)/根号(x)*(1+x)令t=根号x x=t^2∫arctan t/t(1+t^2)dt^2怎么继续做?
∫arctan根号(x)/根号(x)*(1+x)
令t=根号x
x=t^2
∫arctan t/t(1+t^2)dt^2
怎么继续做?

∫arctan根号(x)/根号(x)*(1+x)令t=根号x x=t^2∫arctan t/t(1+t^2)dt^2怎么继续做?
解析:
令t=√x,则x=t²,dx=dt²=2tdt
所以原式=∫(arctan√x)/√x(1+x)dx
=∫[arctant/t(1+t²)]*2tdt
=2∫arctant/(1+t²)dt
=2∫arctant d(arctant)
=2*1/2*(arctant)²+C.
=(arctan√x)²+C.

∫arctan√(x)/[√(x)*(1+x)]dx
=2∫arctan√(x)/[(1+x)]d√x
=2∫arctan√(x)darctan√(x)
=[arctan√(x)]^2+C