Read in some x-y data and then find a least-squares fit to the data as a linear combination of given functions, or as a nonlinear function.

Read in arrays x and y from xyL.dat and find the best 5th degree polynomial fit

 read xyL.dat x y
 scalar\fit a0 a1 a2 a3 a4 a5
 fit y = a0+a1*x+a1*x^2+a2*x^3+a3*x^4+a4*x^5
 

Read in arrays x and y from xyN.dat and find the best fit to y(x) = a0*exp(a1*x)*sin(a2*x+a3)

 read xyN.dat x y
 scalar\fit a0 a1 a2 a3
 a0 = 5
 a1 = -.5
 a2 = 1.5
 a3 = .5
 fit y = a0*exp(a1*x)*sin(a2*x+a3)
 

  Read data from files
  Define and plot a function