# What is the derivative of x + 1/x?

$1 - \frac{1}{x} ^ 2$
$\frac{d}{\mathrm{dx}} \left(x + \frac{1}{x}\right) = \frac{d}{\mathrm{dx}} \left(x + {x}^{- 1}\right)$
$= 1 - {x}^{- 2}$