(1)已知tan(π/4+α)=2,求tanα,sin2α+sin^2α+cos2α
问题描述:
(1)已知tan(π/4+α)=2,求tanα,sin2α+sin^2α+cos2α
还有一题(2)已知0谢拉
答
1.tan(π/4+α)=2 [tan(π/4)+tanα]/[1-tan(π/4)*tanα]=(1+tanα)/(1-tanα)=2 tanα=1/3 2.(sin2α·cosα-sinα)/(sin2α·cos2α) =(2sinα·cosα·cosα-sinα)/(2sinα·cosα·cos2α) =sinα(2cosα...