Originally Posted by

**RogueDemon** State the transformations:

$\displaystyle f(x) = x^2$

$\displaystyle g(x) = 9x^2$

My answer:

Vertical Expansion by $\displaystyle 9$ OR Horizontal Compression by $\displaystyle \frac{1}{9}$.

Text Answer:

Vertical Expansion by $\displaystyle 9$ OR Horizontal Compression by $\displaystyle \frac{1}{3}$.

Just wondering, how is the compression factor $\displaystyle \frac{1}{3}$? Is it because $\displaystyle 9x^2 = (3x)^2$, therefore $\displaystyle 3x = $Horizontal Compression by $\displaystyle \frac{1}{3}$?

Also, is a Horizontal Compression by $\displaystyle \frac{1}{3}$ the same thing as a Horizontal Expansion by $\displaystyle 3$? The terms "Expansion" and "Compression" become quite confusing when used with whole numbers and fractions. It's hard to remember which one refers to which.