# How do you find the derivative of the inverse of y = 4x + 2x?

Aug 21, 2015

Assuming that the question wants the derivative of the inverse function ${f}^{-} 1$ if $f \left(x\right) = 4 x + 2 x$, the answer is $\frac{1}{6}$

#### Explanation:

$f \left(x\right) = 4 x + 2 x = 6 x$, so ${f}^{-} 1 \left(x\right) = \frac{1}{6} x$.

$\frac{d}{\mathrm{dx}} \left(\frac{1}{6} x\right) = \frac{1}{6}$