# Math Help - Nondifferentiable function

1. ## Nondifferentiable function

For the function f(x) = (x-6)^7/9 find the x-value at which the derivative does not exist.

2. Originally Posted by BOOTYBOY
For the function f(x) = (x-6)^7/9 find the x-value at which the derivative does not exist.
$f'(x)=\frac{7}{9(x-6)^{\frac{2}{9}}}$. Now where is that undefined?