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x^4./根号下(1-x^2)^3不定积分
人气:210 ℃ 时间:2020-06-07 04:58:42
解答
令x=sinu,则:u=arcsinx,dx=cosudu.
∴∫{x^4/√[(1-x^2)^3]}dx
=∫[(sinu)^4/(cosu)^3]cosudu
=∫{[1-(cosu)^2]^2/(cosu)^2}du
=∫[1/(cosu)^2]du-2∫du+∫(cosu)^2du
=tanu-2u+(1/2)∫(1+cos2u)du
=tanu-2u+(1/2)∫du+(1/4)∫cos2ud(2u)
=sinu/cosu-(1/2)arcsinx+(1/4)sin2u+C
=x/√(1-x^2)-(1/2)arcsinx+(1/2)sinucosu+C
=x/√(1-x^2)-(1/2)arcsinx+(1/2)x√(1-x^2)+C.
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