Secant Method for Solving non-linear equations in MATLAB(mfile)

% Secant Algorithm

 % Find the root of y = cos(x) from 0 to pi.

 f = @(x) (cos(x));

 p0 = input('Enter 1st approximation, p0: ');

 p1 = input('Enter 2nd approximation, p1: ');

 n = input('Enter no. of iterations, n: ');

 tol = input('Enter tolerance, tol:  ');

 i = 2;

 f0 = f(p0);

 f1 = f(p1);

 while i <= n

    p = p1-f1*(p1-p0)/(f1-f0);

    fp = f(p);

    if abs(p-p1) < tol

       fprintf('\nApproximate solution p = %11.8f\n\n',p);

       break;

    else

       i = i+1;

       p0 = p1;

       f0 = f1;

       p1 = p;

       f1 = fp;

    end

 end

Output:

>> Secant_method_m

Enter 1st approximation, p0: 1

Enter 2nd approximation, p1: 2

Enter no. of iterations, n: 30

Enter tolerance, tol:  0.0001

Approximate solution p =  1.57079633

>>