Answer:
The period of 6/7 seconds or 0.857 seconds.
Explanation:
The period of any given trigonometric function is given by:
[tex]y=a cos(bx+c)d\\\\Period:\\\\T=\frac{2\pi }{b}[/tex]
In this function b is [tex]\frac{7\pi }{3}[/tex]
So, the period for the given function is calculated as follows:
[tex]T=\frac{2\pi }{b}=\frac{2\pi }{\frac{7\pi }{3}}=\frac{6}{7} s=0.857s[/tex]
