Question

What is the equation of the normal line of `f(x)=xln(3^(1/x))` at `x=9`?

Answer 1

The normal line at `x=9` is the vertical line `x=9`

Explanation:

`f(x) = x[ln(3^(1/x))] = x [1/x ln(3)] = ln(3)`

So the graph of `f` is a horizontal line and the normal line if vertical.

The vertical line with `x=9` has equation `x=9`.