
• The power rule says $\dfrac {d}{dx}(x^n) = nx^{n-1}$ where $x$ is a variable and $n$ is a number.
• The formula for differentiating an exponential function is $\dfrac {d}{dx}(a^x) = a^x \ln (a)$.
• The formula for differentiating a logarithmic function is $\dfrac {d}{dx}(\log _a(x)) = \dfrac {1}{x \ln (a)}$, where $a$ is a number and $x$ is a variable.
$\dfrac {d}{dx} \sin (x) = \cos (x)$
$\dfrac {d}{dx} \cos (x) = - \sin (x)$