13.6 Vertical stretches in transformations
Vertical stretches in transformations
Lessons

a)
Sketch the following functions:
$\left( y \right) = {x^2} + 2$ $\left( {2y} \right) = {x^2} + 2$ $\left( {\frac{y}{3}} \right) = {x^2} + 2$ 
b)
Compared to the graph of $\left( y \right) = {x^2} + 2$:
• $\left( {2y} \right) = {x^2} + 2$ is a vertical stretch about the xaxis by a factor of ____________.
• $\left( {\frac{y}{3}} \right) = {x^2} + 2$ is a vertical stretch about the xaxis by a factor of ____________.


a)
$y = \frac{1}{2}f\left( x \right)$

b)
$y = \frac{4}{3}f\left( x \right)$

c)
In conclusion:
• $\left( y \right) \to \left( {2y} \right)$: vertical stretch by a factor of ________ ⇒ all $y$ coordinates ______________________.
• $\left( y \right) \to \left( {\frac{3}{4}y} \right)$: vertical stretch by a factor of ________ ⇒ all $y$ coordinates ______________________.
