y=sinx的图像→向左移5π/6个单位长度→y=sin[x+5π/6]的图像→y=sin[(x+π/3)+π/2]的图像→y=cos(x+π/3)的图像→纵坐标不变,横坐标缩小到原来的1/3→y=cos(3x+π/3)的图像或者y=sinx的图像→纵坐标不变,横坐标缩...