化解(cosa+sina)^2-2sin^2a

化解(cosa+sina)^2-2sin^2a 2sina(sina+cosa)的化解过程 已知(sina+cosa)/(sina-cosa)=3 则2sin'a+(sina-cosa)'=? 3cosa-2sina=根号13,则3sin-cosa/3sin+cosa等于多少 sina=2cosa,求(1)3sina+2cosa(2)sin²a+sina×cosa+3 已知sinα=2cosα,求sina+5cosa/-2cosa+sinasina+5cosa/-2cosa+sina 证明sin^2a+sin^2β+1>sina*cosa+sina+sinβ 3sina=2cosa 则(cosa-sina/cosa+sina)+(cosa+sina/cosa-sina)=______ 3sina=2cosa 则(cosa-sina/cosa+sina)+(cosa+sina/cosa-sina)=______ sina+cosa/sina-cosa=2 求sin^2a-2sinacosa+1 求证：cosa(cosa-cosb)+sina(sina-sinb)=2sin^2a-b/2 cos^2a-sin^2a=(cosa+sina)(cosa-sina)吗?求解 已知tana=-3,求sina+2cosa/cosa-3sina和sin^2a-sinacosa 已知(sina+cosa)/(sina-cosa)=2,则：(3sina+cosa)/(2sina+3cosa)=?sin^2a-2sinacosa+1=? 已知sina+cosa/sina-cosa=2,计算下列各式的值（1）3sina+cosa/2sina+3cosa(2)sin^a-2sinacosa+1. 三角函数恒等式求证：cosa + sina / cosa - sina + cosa - sina / cosa + sina = cos＾2a - sin＾2a / 2 已知tana=3,求下列各式的值 1.sina+cosa/sina-cosa 2.sina.cosa 3.sin^2 a+sina.cosa cosa/(sina+sin3a)=cosa/(2sin(2a)cosa)怎么来的啊