積分......
回答 (2)
∫(cosx)^3 dx
=∫(cosx)^2 cosx dx (將cosx其中一個次方甩出黎)
=∫[1-sinx^2] d(sinx) (用1=cosx^2 + sinx^2) ( d(sinx)=cosx dx)
=∫1d(sinx) - ∫sinx^2 d(sinx)
=sinx - (sinx^3)/3 + C (C: constant)
收錄日期: 2021-04-24 00:42:20
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