Question

y=sin(2/3π+3x）的图像,只需将y=cos3x的图像如何变化?

Answer 1

y=sin(2π/3+3x)=sin[π-(2π/3+3x)]=sin(π/3-3x)=cos[π/2-(π/3-3x)]=cos(3x+π/6)=cos(3(x+π/18))

y=cos3x向左平移π/18得到