# Math Help - derivative functions

1. ## derivative functions

y= 1/x find dy/dx

2. Originally Posted by vinson24
y= 1/x find dy/dx
If $y=x^n$ then $\frac{dy}{dx} = nx^{n-1}$.

Here $y=\frac{1}{x}$. Keep in mind, $x \neq 0$

Do you remember your index laws? One is $a^{-n} = \frac{1}{a^n}$.

Using this index law, we turn the function into

$y = x^{-1}$.

So the derivative is $\frac{dy}{dx} = -1 x^{-2} = -\frac{1}{x^2}$. Clearly, once again, $x \neq 0$.