Functions > Data Analysis > Curve Fitting > Sinusoidal Regression
  
Sinusoidal Regression
sinfit(vx, vy, vg)—Returns a vector containing the coefficients for a sine curve of the form a · sin(x + b) + c that best approximates the data in vx and vy using guess values in vg.
The sinfit function employs the Levenberg-Marquardt method for minimization.
Arguments
vx, vy are vectors of real data values of the same length, corresponding to the x and y values in the data set. There must be at least three data points.
vg is a three-element vector of real guess values for the parameters a, b, and c in the sinusoidal fit equation.