最佳回答取２０分：兩條Trigonometric Relations問題
2007-05-23 3:28 am
1.Find the measure of θ if cos(30∘+4θ) = cos(2θ+30∘)/tan(60∘-2θ)
2. Prove the following isentities.
(a) sin(90∘-θ)sinθ/sinθ-1 + cos(90∘-θ)cosθ/sinθ+1 ≡ -2sinθ/tan(90∘-θ)
(b) [cosθtanθ+cos(90∘-θ)tan(90∘-θ)]² - 2sinθsin(90∘-θ) ≡1
希望大家幫下手啦
回答 (3)
2007-05-28 12:41 am
✔ 最佳答案
1.Find the measure of θ if cos(30∘+4θ) = cos(2θ+30∘)/tan(60∘-2θ)Ans:5°
2. Prove the following isentities.
(a) sin(90∘-θ)sinθ/sinθ-1 + cos(90∘-θ)cosθ/sinθ+1 ≡ -2sinθ/tan(90∘-θ)
(b) [cosθtanθ+cos(90∘-θ)tan(90∘-θ)]² - 2sinθsin(90∘-θ) ≡1
對不起,本人不太會prove identities=]
希望幫到你啦
參考: By 明智光秀
2007-06-19 10:40 pm
自問自答
2007-05-23 3:44 am
1.tan x=3
sin x/cos x=3
cos x=1/3‧sin x
sin^2 x + cos^2 x = 1
1/9‧sin^2 x+sin^2 x=1
sin^2 x=9/10
sin x=3/√10
sin x/cos x=3
cos x=1/3‧sin x
sin^2 x + cos^2 x = 1
1/9‧sin^2 x+sin^2 x=1
sin^2 x=9/10
sin x=3/√10
收錄日期: 2021-04-28 13:22:23
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