已知sin(π/2+α)-cos(3π/2-α)=1/5(π/2

问题描述:

已知sin(π/2+α)-cos(3π/2-α)=1/5(π/2

数学人气:532 ℃时间:2020-01-26 15:06:54
优质解答
==》cosa+sina=1/5cos^a+2cosasina+sin^a=1+2cosasina=1/25cosasina=-12/25cosa<0,-sina<0 1-2cosasina=(cosa-sina)^=49/25cosa-sina=-7/25tana=sina/cosa=-12/2=-6(π/2cos(3π/2-α)=sina
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==》cosa+sina=1/5cos^a+2cosasina+sin^a=1+2cosasina=1/25cosasina=-12/25cosa<0,-sina<0 1-2cosasina=(cosa-sina)^=49/25cosa-sina=-7/25tana=sina/cosa=-12/2=-6(π/2cos(3π/2-α)=sina