Fitting with formula: y = 2*a0*sin(2*x)*(sin(x)^2-a1)
Initial guesses:
        a0 = -76
        a1 = 0.7
Tolerance = 0.01
Relative error in the sum of squares is at most tol.
Computed values:
        a0 = -76.4579
        a1 = 0.76948

Chi-square: 0.0263933
Correlation coefficient: 0.999998
RMS per cent error: 0.00539027
Theil U coefficent: 0.00157046