# What happens when the a (amplitude) of a sine graph is negative -2 sin (1/4 x)?

if you choose $x = \pi$ yo get $\sin \left(\frac{\pi}{4}\right) = \frac{\sqrt{2}}{2}$ but with minus 2 in front your amplitude becomes: $- 2 \frac{\sqrt{2}}{2} = - \sqrt{2}$:
$y = 2 \sin \left(\frac{x}{4}\right)$
$y = - 2 \sin \left(\frac{x}{4}\right)$