Given the function;
[tex]y=\frac{2}{3}\cos (\frac{4}{7}x)+2[/tex][tex]\begin{gathered} \text{But the frequency f is given as;} \\ f=\frac{2\pi}{T} \\ \text{Where T is the period} \\ f=\frac{4}{7} \end{gathered}[/tex][tex]\begin{gathered} \frac{4}{7}=\frac{2\pi}{T} \\ 4T=14\pi \\ T=\frac{14\pi}{4} \\ T=\frac{7\pi}{2} \\ \end{gathered}[/tex]CORRECT OPTION: A
