1.(sinθ=cosθ)^2 - 2sinθcosθ
2.tanθ-(sin^3θ/cosθ)
唔趺要步驟,thanks
中3三角恆等式hw~helps!!
2009-05-04 6:53 am
回答 (1)
2009-05-04 7:02 am
✔ 最佳答案
1.(sinθ+cosθ)2 - 2sinθcosθ=(sin2θ+cos2θ+2sinθcosθ)- 2sinθcosθ
=(1+2sinθcosθ)- 2sinθcosθ
=1
2.tanθ-(sin3θ/cosθ)
=tanθ-(sin2θtanθ)
=tanθ(1-sin2θ)
=tanθcos2θ
=sinθcosθ
收錄日期: 2021-04-23 20:41:33
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20090503000051KK02319