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matlabsumpolynomial-mathbuilt-in

Summing two polynomials

I'm looking for a built-in Matlab function that sums two polynomial.

Example:

\ p_1(x) = 500x^5 + 400x^4 + 300x^3 + 200x^2 + 100x + 50 \ p_2(x) = \qquad\qquad\qquad\qquad\;\, 3x^3 + \quad 2x^2 + \quad\;\, x + \;\; 5 \ p_s(x) = 500x^5 + 400x^4 + 303x^3 + 202x^2 + 101x + 55

p1(x) and p2(x) are represented in code standard Matlab vectors:

p1 = [500 400 300 200 100 50];
p2 = [3 2 1 5];

How do I sum these two polynomials to get ps(x) with using built-in Matlab function(s); without writing an explicit m-file function?

Solution

  • I sure hope there is a nicer way of doing it (I'd probably put this into a helper function), but this seems to work just fine:

    [zeros(1, size(p1,2)-size(p2,2)) p2] + [zeros(1, size(p2,2)-size(p1,2)) p1]

ans =

   500   400   303   202   101    55