Question

Find the period of the function y = 2∕3 cos(4∕7x) + 2.A) 7∕4πB) 4∕7πC) 7∕2πD) 3π

Answer 1

Given:

The function is,

`y=(2)/(3)\cos ((4)/(7)x)+2`

Step-by-step explanation:

The period of cosine function y = Acos (Bx+C) + D is,

`\text{Period}=(2\pi)/(B)`

For the given function B = 4/7. So period of the function is,

`\begin{gathered} \text{Period=}(2\pi)/((4)/(7)) \\ =2\pi\cdot(7)/(4) \\ =(7\pi)/(2) \\ =(7)/(2)\pi \end{gathered}`

So option C is correct.