Answer:
![\displaystyle 4](https://img.qammunity.org/2023/formulas/mathematics/high-school/ia9t2emg5lc1tw8upgf0jun0aourywccy3.png)
Step-by-step explanation:
![\displaystyle y = Acos(Bx - C) + D](https://img.qammunity.org/2023/formulas/mathematics/high-school/9ivqum9nh41ohekojn4dbjomr5sws14oo9.png)
When working with a trigonometric equation like this, always remember the information below:
![\displaystyle Vertical\:Shift \hookrightarrow D \\ Horisontal\:[Phase]\:Shift \hookrightarrow (C)/(B) \\ Wavelength\:[Period] \hookrightarrow (2)/(B)\pi \\ Amplitude \hookrightarrow |A|](https://img.qammunity.org/2023/formulas/mathematics/high-school/1nj1p4jxsov4iwis8hahnjuj9lnbynrkdj.png)
So, the first procedure is to find the period of this graph, and when calculated, you should arrive at this:
![\displaystyle \boxed{(1)/(4)} = (2)/(8\pi)\pi](https://img.qammunity.org/2023/formulas/mathematics/high-school/m3ziyynq47zt2zaqkl5yxr2wvbkmnmv2cy.png)
You will then plug this into the frequency formula,
Look below:
![\displaystyle (1)/(4)^(-1) = F \\ \\ \boxed{4 = F}](https://img.qammunity.org/2023/formulas/mathematics/high-school/182kfcbnfcsuvmw5vd1eop5nrniorryxsl.png)
Therefore, the frequency of motion is four hertz.
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