Solve for b: $a^2 = b^2 c^2 - b^4$ Given $c>b$ which leads to $b^2 c^2 - b^4 > 0$ is it possible to solve for b in the equation 
$$a^2=b^2 c^2 - b^4$$

Hint: Let $b^2=w$ so you have the equation $w^2-c^2w+a^2=0$. Now solve to $w$.
