化簡下列各題
1.2 tanθ/sinθ
2. 3 sin^2θ+3cos^θ
3. -4cos^2θ- 4sin^2θ
4. tan^2θcos^2θ+cos^2θ
5. 1/sinθ- cos^2θ/ sinθ
6. 1/coa^2θ- tan^2θ
7. 3cosθ/sin(90°-θ)
8. sin(90°-θ)/cos(90°-θ)×tanθ
9. tanθ/cos(90°-θ) - 1/sin(90°-θ)
三角比的化簡
2008-05-10 5:03 pm
回答 (2)
2008-05-10 5:20 pm
✔ 最佳答案
1. 2 tanθ/sinθ =2(sinθ/cosθ)/sinθ
=2/cosθ
2. 3 sin2θ+3cos2θ
=3(sin2θ+cos2θ)
=3(1)
=3
3. -4cos2θ- 4sin2θ
=-4(sin2θ+cos2θ)
=-4(1)
=-4
4. tan2θcos2θ+cos2θ
=(sin2θ/cos2θ)cos2θ+cos2θ
=sin2θ+cos2θ
=1
5. 1/sinθ- cos2θ/ sinθ
=(1-cos2θ) /sinθ
=sin2θ/sinθ
=sinθ
6. 1/cos2θ- tan2θ
=1/cos2θ-(sin2θ/cos2θ)
=(1-sin2θ)/cos2θ
=cos2θ/cos2θ
=1
7. 3cosθ/sin(90-θ)
=3cosθ/cosθ
=3
8. sin(90-θ)/cos(90-θ)tanθ
=cosθ/sinθ(sinθ/cosθ)
=1
9. tanθ/cos(90-θ) - 1/sin(90-θ)
=(sinθ/cosθ)/sinθ-1/cosθ
=1/cosθ-1/cosθ
=0
2008-05-10 5:11 pm
收錄日期: 2021-04-23 20:33:13
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20080510000051KK00475