θ=?
更新1:
Is '2 sin x cos x=sin 2x' a formular?
三角學的題目
回答 (2)
2009-05-17 5:20 am
✔ 最佳答案
sinθcosθ=1/41/2sin2θ=1/4
sin2θ=1/2
2θ= nπ+[π(-1)^n]/6, where n is a +ve integer
θ=nπ/2+[π(-1)^n]/12
2009-05-16 21:47:13 補充：
sin2x =2sinxcosx, this is the double angle formula
參考: me, me
2009-05-17 5:21 am
sin x cos x = 1/4
2 sin x cos x = 1/2
sin 2x = 1/2= sin 30
2x = 30
x = 15.
2 sin x cos x = 1/2
sin 2x = 1/2= sin 30
2x = 30
x = 15.
收錄日期: 2021-04-25 22:39:24
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20090516000051KK01859