Given:
The sine function is:
[tex]y=\dfrac{1}{3}\sin (2x)[/tex]
To find:
The frequency of the graph of given function.
Solution:
If a sine function is defined as:
[tex]y=A\sin(Bx+C)+D[/tex]
Then, the frequency of the sine function is:
[tex]f=\dfrac{B}{2\pi}[/tex]
We have,
[tex]y=\dfrac{1}{3}\sin (2x)[/tex]
Here, [tex]B=2[/tex]. So, the frequency of the given function is:
[tex]f=\dfrac{2}{2\pi}[/tex]
[tex]f=\dfrac{1}{\pi}[/tex]
Therefore, the correct option is D.