This tutorial shows the required steps to find best curve fit.
  1. Select data series on left panel [Points].
  2. Select menu item <Fit><Best Function>.
  3. The 'Find the best line' Wizard appears.
  4. On step 1 choose X and Y ranges and weighting scheme.
  5. On step 2 select 'Find equation' item 'Y=f(X)'.
  6. On step 4 select 'All functions', and select 'Fourier' item unchecked.
  7. On step 5 click Start. Fitting process runs.
  8. New graphs appear. See how fit curves conform your data.
  9. Select the number of best fit functions '3' to plot.
  10. Select menu item <View><Fitting log>.