difference between 2 exponentially smoothed average

[Guest]

I would like to subtract a 12 day exponentially smoothed average from a 26 day exponentially smoothed average and then I have to do a 9 day exponentially smoothed average of the difference.Then I have to plot the difference of the 2 exponentially smoothed averages and the 9 day exponentially smoothed average on a graph.

Thanks in advance,

rgds.