SiNx; sin (x / 2) = 8; 5, then cosx =? sinx:sin (x / 2) = 8:5, then cosx =?

SiNx; sin (x / 2) = 8; 5, then cosx =? sinx:sin (x / 2) = 8:5, then cosx =?

sinx＝2sin(x/2)cos(x/2)
Cos (x / 2) = 4 / 5
cosx＝2cos^2(x/2)－1＝2×(4/5)^2－1＝7/25

What kind of transformation can y = sin (Wx + φ) be obtained from y = SiNx

If φ is positive, it shifts to the left; if it is negative, it shifts to the right
First, shift ┇ φ ┋ units to the left / right, then the abscissa remains unchanged, and the ordinate becomes the original (┇ 1 / ω ┋) times
First, the abscissa is invariable, the ordinate is changed to the original (┇ 1 / ω┋) times, and then the abscissa is shifted to the left or right (┇ φ / ω┋) times

How to transform the image of y = SiNx to y = sin3x? How to transform the image of y = sin3x to y = sin (3x + π / 3)?
How to transform the image of y = sin (3x + π / 3) to y = 3sin (3x + π / 3)?
Be more specific

The abscissa of the image with y = SiNx is expanded to 3 times of the original, and y = sin3x is obtained
The image of y = sin3x moves π / 9 units to the left to get y = sin (3x + π / 3)