Please help me to do this Math below:
(tan30°sin60°+tan60°cos60°)^2
__________________________
(cos^2 30°+cos^2 60°)
Maths(sine,cosine)
2008-03-22 12:18 am
回答 (2)
2008-03-22 1:13 am
✔ 最佳答案
(tan30°sin60°+tan60°cos60°)^2/(cos^2 30°+cos^2 60°) =[(1/√3)(√3/2)+(√3)(1/2)]^2/[(√3/2)^2+(0.5)^2]
=(1/2+√3/2)^2/(3/4+0.25)
=(1/2+√3/2)^2
=1/4+√3/2+3/4
=1+√3/2
=(2+√3)/2
參考: Myself
2008-03-22 1:08 am
(tan30°sin60° +tan60°cos60°)^2
-------------------------------------------
(cos^2 30°+ cos^2 60°)
cos60° sin60°
( ----------- x sin60°+ ------------- x cos60° ) ^2
sin60° cos60°
=---------------------------------------------------------------------
cos^2 30°+ sin^2 30°
(cos60°+ sin60°)^2
=----------------------------------
1
=cos^2 60° + 2cos60°sin60° + sin^2 60°
=1 + 2 x 1/2 x root3 /2
=1 + root3 /2
-------------------------------------------
(cos^2 30°+ cos^2 60°)
cos60° sin60°
( ----------- x sin60°+ ------------- x cos60° ) ^2
sin60° cos60°
=---------------------------------------------------------------------
cos^2 30°+ sin^2 30°
(cos60°+ sin60°)^2
=----------------------------------
1
=cos^2 60° + 2cos60°sin60° + sin^2 60°
=1 + 2 x 1/2 x root3 /2
=1 + root3 /2
收錄日期: 2021-05-01 15:56:44
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20080321000051KK01836