數學Prove問題

Prove tanθ+cosθ/cos(90度-θ)=1/sinθcosθ

L.H.S.
=tanθ+cosθ/cos(90度-θ)
=tanθ+cosθ/sinθ <<because cos(90度-θ)= sinθ
=sinθ/cosθ+cos/sinθ  <<because tanθ= sinθ/cosθ
=(sin2 θ+cos2θ)/(cosθsinθ) <<by 通分母
=1/sinθcosθ <<because sin2 θ+cos2θ=1
=R.H.S.

2012-09-01 16:50:07 補充：
P.S. Sorry 呢度顯示5度, 其實入面個"2"系2次方個"2"

圖片參考：http://imgcld.yimg.com/8/n/HA00100646/o/701209010051113873365280.jpg


圖片參考：http://imgcld.yimg.com/8/n/HA00100646/o/701209010051113873365281.jpg

Hope I can help you.