Without speeding up it would take 5 1/3 seconds.. not sure if it speeds up in the question?
Answer:

Step-by-step explanation:
We are asked to find the equation of mid-line of the given sinusoidal function.
Since the mid-line of a sinusoidal function is the line that runs between the maximum and minimum y-values of the function. We can consider it the middle y-value.

We can see from our given graph that the maximum value of our function is 5 and minimum value of our function is -5.
Upon substituting these values in mid-line formula we will get,

Therefore, the equation of the mid-line of the given sinusoidal function is
.
280,706 is the standard form
Step-by-step explanation:
Below is an attachment containing the solution.