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分部积分[x^2arctanx/(1+x^2)]dx

题目详情
分部积分[x^2arctanx/(1+x^2)]dx
▼优质解答
答案和解析
∫x^2arctanx/(1+x^2)dx
=∫(x^2+1-1)arctanx/(1+x^2)dx
=∫arctanxdx-∫arctanx/(1+x^2)dx
=xarctanx-∫ x/(1+x^2)dx-∫arctanxd (arctanx)
=xarctanx-(1/2)∫ 1/(1+x^2)d(x^2)-(1/2)(arctanx)^2
=xarctanx-(1/2)ln(1+x^2)-(1/2)(arctanx)^2+C