Simplify
sin(180-θ)tan(90+θ)/cos(180+θ)
sin(180-θ)tan(90+θ)/cos(180+θ)
2007-10-23 8:13 am
回答 (2)
2007-10-23 8:19 am
✔ 最佳答案
sin(180-θ)tan(90+θ)/cos(180+θ)=sinθ (-1/tanθ) /(-cosθ)
=sinθ(cosθ/sinθ)/cosθ
= 1
2007-10-23 8:21 am
sin(180-θ)tan(90+θ)/cos(180+θ)
= sin(θ)[-1/tan(θ)] / [-cos(θ)]
= sin(θ)[1/tan(θ)] / cos(θ)
= tan(θ) / tan(θ)
= 1
[Explanations]
Line 2:
sin(180-θ) = sin(θ)
tan(90+θ) = -1/tan(θ)
cos(180+θ) = -cos(θ)
Line 4:
sin(θ)/cos(θ) = tan(θ)
If there is a mistake, please inform me!
= sin(θ)[-1/tan(θ)] / [-cos(θ)]
= sin(θ)[1/tan(θ)] / cos(θ)
= tan(θ) / tan(θ)
= 1
[Explanations]
Line 2:
sin(180-θ) = sin(θ)
tan(90+θ) = -1/tan(θ)
cos(180+θ) = -cos(θ)
Line 4:
sin(θ)/cos(θ) = tan(θ)
If there is a mistake, please inform me!
參考: My Maths knowledge
收錄日期: 2021-04-13 14:05:57
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20071023000051KK00053