来自刘国荣的问题
已知cosα-sinα=3√2/5,若17兀/12
已知cosα-sinα=3√2/5,若17兀/12
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2020-06-24 18:31
已知cosα-sinα=3√2/5,若17兀/12
已知cosα-sinα=3√2/5,若17兀/12
cosα-sinα=3√5/5平方得1-sin2a=9/5sin2a=-4/517π/12<α<7π/4cos2a=-3/5tan(π/4+α)=(1+tana)/(1-tana)=(sina+cosa)/(cosa-sina)=(sina+cosa)^2/(cos^2a-sin^2a)=(1+sin2a)/cos2a=(1/5)/(-3/5)=-1/3...