专题文章
时长:00:00更新时间:2024-12-19 16:26:36
接下来,我们计算∫(0,1)ln(1+r^2)rdr。应用分部积分法,令u=ln(1+r^2),dv=rdr,则du=(2r/(1+r^2))dr,v=(1/2)r^2。根据分部积分公式,有。∫ln(1+r^2)rdr = (1/2)r^2ln(1+r^2) - ∫(1/2)r^2(2r/(1+r^2))dr。化简后得:∫ln(1+r^2)rdr = (1/2)r^2ln(1+r^2) - ∫r^2/(1+r^2)dr。进一步化简,∫r^2/(1+r^2)dr = ∫(1 - 1/(1+r^2))dr = r - arctan(r) + C。因此,∫ln(1+r^2)rdr = (1/2)r^2ln(1+r^2) - (1/2)r^2 + r - arctan(r) + C。
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