# What is the amplitude, period and phase shift for y = 4cos(pix)?

Feb 24, 2018

Amplitude

This is described by the a parameter, or the number directly to the left of the sine or cos, in this case $4$.

Period

The period is given by $\frac{2 \pi}{b}$, where $y = a \cos \left(b \left(x - c\right)\right) + d$.

Thus the period is

$\frac{2 \pi}{\pi} = 2$

Phase Shift

There is no phase shift because $c = 0$.

Hopefully this helps!