我唔明點
∫(sin^3xcos^5x)dx =>∫(sin^3xcos^4x)dsinx同埋
∫(sin^3xcos^5x)dx =>∫(sin^3xcos^4x)dsinx
麻煩你解釋下...詳細d..thx
integration 一問 urgent
2009-02-01 4:42 am
回答 (1)
2009-02-01 4:49 am
✔ 最佳答案
因為d(sinx)/dx=cosxd(sinx)=(cosx)dx
其含意為當x改變很小時﹐(sinx)的改變量=(cosx)*(x的改變量)
∫(sin^3xcos^5x)dx
=>∫(sin^3xcos^4x cosx dx
類似地∫(sin^3xcos^5x)dx =>∫(sin^3xcos^4x)dsinx
你做積分時用這個方法比慢慢寫substitution快很多﹐又不易出錯
=> ∫(sin^3xcos^4x)dsinx
收錄日期: 2021-04-26 13:15:01
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20090131000051KK01833