help me, why is it invalid use of operator?

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Jefferson Pons
Jefferson Pons on 21 Jul 2020
Commented: David Hill on 21 Jul 2020
can you guys help me? this is the code im having problem with:
% Simpson's 1/3 Rule for finding integration of x
the function that i want to use is this:
please help me. thank you!

Answers (1)

David Hill
David Hill on 21 Jul 2020
Not sure if you have additional constraints, but if your functions are all polynomials, the polyint function works well.
p=[-.0729,1.171,-13.8,4,-1];
intP=diff(polyval(polyint(p),[a,b]));%where a and b are the lower and upper bounds
  2 Comments
David Hill
David Hill on 21 Jul 2020
f=@(x)-.0729*x.^4+1.171*x.^3-13.8*x.^2+4*x-1;%here is how you write the function
David Hill
David Hill on 21 Jul 2020
Where a,b,and n are input like above
f=@(x)-.0729*x.^4+1.171*x.^3-13.8*x.^2+4*x-1;
x=linspace(a,b,n+1);
y=f(x);
intF=(b-a)/3/n*(f(a)+f(b)+4*sum(y(1:2:end))+2*sum(y(2:2:end)));

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