Question

F(x)=4x^2-1 what is the inverse

Answer 1

Let $y = F^{-1}(x)$ and $F(y) = x$

$4y^2 - 1 = x\\4y^2 = x + 1\\y^2 = \frac{x + 1}{4}\\y = \sqrt{\frac{x + 1}{4}}\\f^{-1} = \sqrt{\frac{x + 1}{4}}$