∫ln(4+r平方)dr等于多少
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∫ln(4+r平方)dr等于多少
∫ln(4+r平方)dr等于多少
∫ln(4+r平方)dr等于多少
分部积分之,有
∫ln(4+r²)dr=rln(4+r²)-∫rdln(4+r²)
=rln(4+r²)-∫2r²/(4+r²)dr
=rln(4+r²)-∫[2-8/(4+r²)]dr
=rln(4+r²)+∫8/(4+r²)dr -2r
=rln(4+r²)+4arctan(r/2) -2r