標題:
Application of trigonometry
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發問:
simplify the following expressionsa)cosθ - cosθsin^2θb)(2sin^2θ/tan^2θ)+cos^2θc)sin(90°-θ) cos^2θ+cosθsin^2θ--------------------------------------------------------------------------evaluate the following expressionsa)cos^(2)... 顯示更多 simplify the following expressions a)cosθ - cosθsin^2θ b)(2sin^2θ/tan^2θ)+cos^2θ c)sin(90°-θ) cos^2θ+cosθsin^2θ -------------------------------------------------------------------------- evaluate the following expressions a)cos^(2) 72°+cos^(2)18°sin90° b)3-cos^(2)72°-cos^(2)18° -------------------------------------------------------------------------- True bearing Compass bearing ? ------------------ N25°E ? ---------------------- S41°E 092° --------------------- ? 331° ------------------ ?
最佳解答:
1. (a) cosθ - cosθsin^2θ=cosθ(1-sin^2θ)=cosθcos^2θ=cos^3θ (b)(2sin^2θ/tan^2θ)+cos^2θ=(2sin^2θ)/(sin^2θ/cos^2θ)+cos^2θ =2cos^2θ+cos^2θ=3cos^2θ (c)sin(90°-θ) cos^2θ+cosθsin^2θ=cosθ cos^2θ+cosθsin^2θ =cosθ (cos^2θ+sin^2θ)=cosθ 2. (a)cos^(2) 72°+cos^(2)18°sin90°=cos^(2)(90°-18°)+cos^(2)18°(1) =sin^(2)18°+cos^(2)18°=1 (b)3-cos^(2)72°-cos^(2)18°=3-cos^(2))(90°-18°)-cos^(2)18° =3-sin^(2))18°-cos^(2)18°=3-1=2 3. (a) true beaing=360°-25°=335° (b) true bearing=270°+41°=311° (c) compass bearing=S(180°-92°)W=S88°W (d) compass bearing=S(360°-331°)E=N29°E
其他解答:1C924F1C0172E337
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