sin?=0.1

sin?=0.1 sin阿尔法+sin贝塔=? sin^20+cos^50=sin^30sin^70= 【证明】Sin A+sin B=2Sin 22 三角函数证明(sinα+sinθ)*(sinα-sinθ)=sin(α+θ)*sin(α-θ)求证(sinα+sinθ)*(sinα-sinθ)=sin(α+θ)*sin(α-θ) sin(10°)+sin(50°)-sin(70°) =sin(10°)+sin(50°)-sin(70°) = sin阿尔法+sin贝塔=?具体点 为什么sin-sin^2=1/4 sin(arccos(2sin(a)))= 解方程|sin x|=-sin x sin(a-15)=-sin(15-a)? 为什么sin(?)=cos(?) sin(arcsin1)=? sin(arcsin3/4) = sinx+sin-x= sin(-π)=? sin2@-sin@=? sin(-1300度)=?