ANSWER
[tex] \frac{1}{2} [/tex]
EXPLANATION
The frequency of a wave function refers to the number of times the graph repeats its cycle within the interval [0,2π]
We can observe explicitly from the graph that the frequency is half.
The period of the given function is 4π
[tex] \frac{2\pi}{b} = 4\pi[/tex]
[tex]b = \frac{2\pi}{4\pi} = \frac{1}{2} [/tex]
Hence the frequency is half.
