I have a set of data points which form an *almost* straight line, but as the line is extended out the data points vary more and more from the median. I've figured out that they're actually forming a sinusoidal wave, which grows in "bandwidth" as it goes further out, and which is centered on a y=mx+b line. I'm guessing the fuction is along the lines of y= (ax)*(sin(bx))+cx+d How do I get that formula out?