we are asked to determine the sine function of the given graph. To do that we will use the general form of the sine function:

"A" is the amplitude and is the maximum value of the function in this case the maximum value is 6, therefore, A = 6.
The value of "c" is the upward shift of the graph, in this case, the graph was an upward shift of 3, therefore, c = 3}
The value of "k" can be found from the period using the following formula:

The period, in this case, is 4, replacing in the previous equation:

Solving for "k":

The value of "b" is the horizontal shift of the graph, in this case is: