# How do you graph y = -cos ( x- pi/4)?

2] the $- 1$ in front of it tells us that the amplitude is $1$ and every time we evaluate the $\cos$ we have to change sign;
3] The $1$ in front of $x$ tells us that the period is $1 = \frac{2 \pi}{p e r i o d}$
and $p e r i o d = 2 \pi$;
4] $- \frac{\pi}{4}$ is the starting angle or initial phase that is the angle when $x = 0$;