## Precalculus (6th Edition) Blitzer

Step 1. Given $y=x^2+6$, we can assume $x=t$ and thus $y=t^2+6$ Step 2. We can also assume $x=\sqrt 6\ tan(t)$ and thus $y=(\sqrt 6\ tan(t))^2+6=6tan^2t+6=6sec^2t$