# Math Help - Simplfying

1. ## Simplfying

If $x=bcos\theta$, where $b>0$ and $\theta$ is acute, simplify $b^2-x^2$

2. Dear Punch,

$b^{2}-x^{2}=b^{2}-b^{2}cos^{2}x=b^{2}(1-cos^{2}x)=b^{2}sin^{2}x$