Stretches

VERTICAL STRETCHES

y = af(x-c)+d
In this the entire graph stretches vertically about the x- axis by a factor of "a" units.

"a" is called as vertical stretch.
So the coordinates of (x,y) translate to (x,ay).
x values does not change.

For example, y = 2f(X)+1
Hence, (x,2y) we have to multiply 2 to y coordinates and add 1.

HORIZONTAL STRETCHES

y = afb(x-c)+d
In this the entire graph stretches horizontally about y-axis by a factor of 1/b.

"b" is called as horizontal stretch.
So the coordinates of (x,y) translate to (1/bx,y). Always remember to multiply x values to reciprocal of "b".
y values does not change.

For example, y = f1/2(x)
Hence, (2x,y) as reciprocal  of 1/2 is 2. Mutilply x values to the reciprocal of 1/2.