MATLAB: How to do the summation of two graphs

summazion of graph

Dear Colleagues,
I have two different graphs with different Y values and x values. it is hard to predict an equation with minimum error for this graph. Is there anyway to plot the sum of following two graphs?
Graph 1=[
414.00 1.00
400.00 1.00
384.00 1.00
381.00 1.00
367.00 1.00
348.00 1.00
321.00 1.19
308.00 1.39
299.00 1.61
279.00 1.78
275.00 2.00
264.00 2.59
272.00 3.39
259.00 3.59
262.00 4.00
274.00 4.59
286.00 5.63
305.00 6.00
341.00 6.19
366.00 6.39
395.00 7.00
408.00 7.19
408.00 7.41
394.00 7.61
408.00 7.81
408.00 8.00
412.00 8.19]
Graph 2=[688.00 1.00
690.00 1.00
672.00 1.00
644.00 1.00
638.00 1.00
660.00 1.01
626.00 1.22
602.00 1.40
602.00 1.59
604.00 1.80
582.00 2.00
560.00 2.22
574.00 2.40
563.00 2.60
557.00 2.79
565.00 3.00
593.00 3.22
602.00 3.40
598.00 3.59
606.00 3.79
592.00 4.00
607.00 4.22
593.00 4.40
603.00 4.59
589.00 4.79
602.00 5.00
581.00 5.22
591.00 5.40
577.00 5.59
585.00 5.80
572.00 6.00
567.00 6.22
559.00 6.40
560.00 6.59
572.00 6.80
592.00 7.00
635.00 7.22
675.00 7.40
702.00 7.59
709.00 7.80
726.00 8.00
728.00 8.22
725.00 8.41
751.00 8.60
775.00 8.80
785.00 9.00
780.00 9.22
794.00 9.41]
1st column is Y axis and second column is x axis.
Thanks in advance.

Best Answer

I don’t understand what you mean by ‘sum’. The two matrices have different numbers of elements, so you can shorten the longer one, or you can interpolate one to the x-values of the other one with interp1 (without extrapolating), but you cannot do any calculations with them as they currently exist.
What equation are you trying to fit to them?