CODEWITHSUNDEEP
matlab
user8253417
user8253417

Reputation: 123

MATLAB: Multiply polynomial coefficient with exponent

Given a polynomial in t and it's inverse, I want to figure out a way in MATLAB to implement the following function (the polynomial is defined using syms):

From c1*t^(x1)+c2*t^(x2)+...+cn*t^(xn), get c1*x1+c2*x2+...+cn*xn

Upvotes: 2

Views: 65

Answers (1)

ThomasIsCoding
ThomasIsCoding

Reputation: 101064

Assuming y = c1*t^(x1)+c2*t^(x2)+...+cn*t^(xn), maybe you can use the following code 

yt = diff(y);
k = subs(yt, t,1)

This is actually a calculus problem, you can use the property that

y'(t) = c1*x1*t^(x1-1) + c2*x2*t^(x2-1) + ... cn*xn*t^(xn-1)

and then evaluate y'(t) with t=1

Upvotes: 2

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