Скачать или смотреть sin(x) - vertical/horizontal compression/stretch New coordinates? Pre-calculus 2

In this video more stress is given to figure out the new coordinates of the stretched or compressed point by scale factor I a I
Note for y=a*sin(x) if I a I greater than 1 then each of the points on the graph will get stretched by scale factor of I a I and for a proper fraction then the graph shrinks or compresses vertically by the scale factor I a I and the new coordinates will be ( x, a*y) thus keeping x coordinate same .
But for y=sin(bx) we will arrange this as y=sin(x/1/b) and for 1/b if proper fraction then there will horizontal compression by scale factor of 1/b and for 1/b greater than 1 then the graph will stretch horizontally by scale factor 1/b thus the new coordinates will be ( 1/b*x,y) y stays the same