[2(cosa)2/sin2a]*[(1-cos2a)/cos2a]化简
问题描述:
[2(cosa)2/sin2a]*[(1-cos2a)/cos2a]化简
答
原式2cos²a (sin²a+cos²a)-(cos²a-sin²a)= ————— * —————————————— (sin(2α)=2sinα·cosα,2sina*cosa cos2a cos(2α)=(cosα)^2-(sinα)^2,cosa 2sin²a (...