## Algebra and Trigonometry 10th Edition

$t=0.75~s$ It represents the time it takes for the pressure to complete an entire cycle.
The period of $cos~x$ is $2\pi$ If $x=\frac{8\pi t}{3}$: $\frac{8\pi t}{3}=2\pi$ $t=\frac{3(2\pi)}{8\pi}=\frac{3}{4}$ $t=0.75$