prove
cos x / (1 + sin x) = (1 - sin x) / cos x
thank you！！！
trigonometry prove
2008-08-12 4:04 pm
回答 (1)
2008-08-12 5:01 pm
✔ 最佳答案
Prove cosx / (1 + sinx) = (1 - sinx) / cosxL.H.S. = cosx / (1 + sinx)
= cosx(1 - sinx) / (1 + sinx)(1 - sinx)
= cosx(1 - sinx) / (1 - sin2x)
= cosx(1 - sinx) / cos2x
= (1 - sinx) / cosx
= R.H.S.
參考: Myself~~~
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