The cosine equation is
![\[ f(x) = 6\cos(x - \pi) + 2 \]](https://img.qammunity.org/2022/formulas/mathematics/high-school/yx1g3mzwv3m1x1d3zsqbmcbuecelh8we3v.png)
To find the cosine equation of the function shown in the image, we follow these steps:
1. Identify the Amplitude: The amplitude of a trigonometric function is the distance from the midline of the graph to a peak or trough. From the graph, we can see that the maximum value is 8 and the minimum is -4. Therefore, the amplitude is

2. Determine the Period: The period of a trigonometric function is the distance along the x-axis to complete one full cycle. On the graph, one full cycle appears to go from 0 to
which is typical for the sine and cosine functions without any horizontal stretch or compression.
3. Calculate the Phase Shift: The phase shift is the horizontal movement of the function. A cosine function starts at its maximum value. By observing the graph, it seems the first maximum point from the y-axis is at
which indicates a phase shift of
to the right.
4. Determine the Vertical Shift: This is the movement of the function up or down on the graph. The midline of the function appears to be at y = 2 , because that's halfway between the maximum of 8 and the minimum of -4. So there is a vertical shift of 2 units up.
5. Formulate the Function: A general cosine function can be written as:
![\[ f(x) = A\cos(B(x - C)) + D \]](https://img.qammunity.org/2022/formulas/mathematics/high-school/2l5ifvuc2v8ow2pc7nhtqammad6ea7woyw.png)
where A is the amplitude,
is the period, C is the phase shift, and D is the vertical shift.
Given our observations:
- Amplitude A = 6
- Period
(since there is no horizontal stretch, B = 1
- Phase Shift C =

- Vertical Shift D = 2
Plugging these into the general form gives us:
![\[ f(x) = 6\cos(x - \pi) + 2 \]](https://img.qammunity.org/2022/formulas/mathematics/high-school/yx1g3mzwv3m1x1d3zsqbmcbuecelh8we3v.png)
This would be the cosine equation of the function shown on the graph. The function has an amplitude of 6, no horizontal stretch (since the period is
a phase shift to the right by
and a vertical shift upwards by 2.