College Algebra & Trigonometry, 2018a

208 CHAPTER 4. FUNCTIONS
Stretching and compressing graphs
The last type of transformation we will examine is that of stretching or compressing
a graph by multiplying inside or outside the parentheses. Starting with our
familiar example function y = f(x):
8
6
4
2
−8 −6 −4 −2
−2
2 4 6 8
−4
−6
−8
If we multiply the function by a constant outside of the parentheses: y =2f(x),
then this will have the effect of multiplying all of the y values by 2. In the table:
x f(x) 2f(x)
−6 0 0
−3 6 12
1 6 12
3 4 8
8 4 8