how to formulate a sine curve of best fit from a graph?

Question

anonymous · Answer

In y=Asin(Bx+C) +D

The D value is the average of all of the y values for each of the points.
The A value is the average of the difference of the largest y value to the D value, and the smallest value to the D value.
The B value is the frequency of the function which is given as this B = (2Pi)/P   where P is the period. (the period being the distance between two maxima or minima, or double the distance between a maxima and minima).

The C value is not so easy and depends on many things so I'm sorry, but that is as far as my ability to explain goes. C controls the horizontal translation but can change based on the B value.