# What is the derivative of sin(x-(pi/4))?

$\cos \left(x - \frac{\pi}{4}\right)$
$\frac{d}{\mathrm{dx}} \sin \left(x - \frac{\pi}{4}\right) = \cos \left(x - \frac{\pi}{4}\right) \cdot \frac{d}{\mathrm{dx}} \left(x - \frac{\pi}{4}\right) = \cos \left(x - \frac{\pi}{4}\right)$