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※ 引述《yuyujack (彎彎領導人習大大)》之銘言:
: http://i.imgur.com/3uazGs7.jpg
: 不知道該怎麼換才好
設u=cosx --> du = -(sinx)dx -->(sinx)dx = (-1)du
∫(sinx)^5 (cosx)^2(dx)
=∫(sinx)^4 (cosx)^2 (sinx)(dx)
=∫[1-(cosx)^2]^2 (cosx)^2 (sinx)(dx)
=∫[1-u^2]^2 u^2(-1) du
=-∫[1-u^2]^2 u^2(du)
=-∫(u^2 -2u^4 + u^6)(du)
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※ 編輯: Tiderus (123.240.102.135), 01/16/2017 13:29:05
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