# Math Help - Trigo...

1. ## Trigo...

Find the maximum and minimum values of y^2 as θ varies between 0 degree and 90 degree inclusive.
Is the amplitude 4?

2. Recall that

$-1 \leq \cos{x} \leq 1$ for all $x$, so

$0 \leq \cos^2{x} \leq 1$ for all $x$.

Therefore $0 \leq \cos^2{(\theta + 30^{\circ})} \leq 1$

and $0 \leq 4\cos^2{(\theta + 30^{\circ})} \leq 4$.