cos(π/3-2x)怎样化等于sin(2x+π/6)
问题描述：
cos(π/3-2x)怎样化等于sin(2x+π/6)
答
cos(π/3-2x)
=cos[2π-(π/3-2x)]
=cos(2x+5π/3)
=cos[π+(2x+2π/3)]
=-cos(2x+2π/3)
=-cos(π/2+2x+π/6)
=sin(2x+π/6)
答
cos(π/3-2x)=cos[(π/2-(2x+π/6)]=sin(2x+π/6)
答
cos(π/3-2x)=cos(π/3)sin(2x+π/6))=sin(π/6)因为cos(π/3)=sin(π/6)所以cos(π/3-2x)=sin(2x+π/6)另一种解法:cos(π/3-2x) 根据公式 cosx=sin(π/2-x) 得=sin[π/2-(π/3-2x)]=sin[（π/2-π/3）+2x]=sin(2x+...
答
cos(π/3-2x)
=sin[π/2-(π/3-2x)]
=sin[（π/2-π/3）+2x]
=sin(2x+π/6)
一个角的余弦值等于它的余角的正弦值
或者说
两角互余，一个角的余弦值等于另一个角的正弦值