The frequency of an oscillation is equal to the reciprocal of the period:
[tex]f= \frac{1}{T} [/tex]
where
f is the frequency
T is the period
In our problem, the period is T=8.01 s, therefore the corresponding frequency is
[tex]f= \frac{1}{8.01 s}=0.12 s^{-1} = 0.12 Hz [/tex]