Question

角α与3π/2-α的正弦函数、余弦函数关系的推导 角α与3π/2+α的正弦函数、余弦函数关系的推导

Answer 1

sin(3π/2-α)=sin[π+(π/2-α)]=-sin(π/2-α)=-cosα

cos(3π/2-α)=cos[π+(π/2-α)]=-cos(π/2-α)=-sinα

sin(3π/2+α)=sin[2π-(π/2-α)]=sin[-(π/2-α)]=-sin(π/2-α)=-cosα

cos(3π/2+α)=cos[2π-(π/2-α)]=cos[-(π/2-α)]=cos(π/2-α)=sinα