MATLAB: New to MATLAB – trying to write bisection method

Question

Hello, I'm brand new to MATLAB and am trying to understand functions and scripts, and write the bisection method based on an algorithm from our textbook. However, I'm running into problems. Could anyone help me please?

Here is my code:

function [f] = Bisection(a,b,Nmax,TOL)
f = x^3  - x^2 + x;
i=1;
BisectA=f(a);
while i <= Nmax
    p=a+(b-a)/2;
    BisectP=f(p);
    if BisectP == 0 || (b-a)/2 < TOL        
        disp('p');
    end
    i=i+1;
    if BisectA*BisectP > 0
        a=p;
        BisectA=BisectP;
    else
        b=p;
    end
end
disp('Method failed after num2str(Nmax) iterations, Nmax=', Nmax);

Thanks.

Answer 1

Your line

f = x^3  - x^2 + x;

does not define a function. Try

f = @(x) x^3  - x^2 + x;