反函數01

\(f \circ f = \left(f\circ g\right) \circ \left(g^{-1} \circ f\right) \)

\(\displaystyle \Rightarrow f \circ f : 3\left(\sqrt{5x+2}\right)^2 -1 = 15x+5, \forall x\geq -\frac{2}{5}\)