numerical_matlab_programs/secant.m at master · svaichu/numerical_matlab_programs · GitHub

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% func --> function is taken by user
% like @(x)(sin(x)) or @(x)(x^2 + x - 1) or any other function
% but use the same format i.e. use paranthesis as used above with '@' and 'x'
% maxerr --> Maximum Error in finding Root

clc;
clear;
maxiter = 100; % max number of iteration before get the answer
f1 = input('Enter the function f(x): ','s');
f = inline(f1);
xn_2 = input('Ener Lower Limit: ');
xn_1 = input('Ener Upper Limit: ');
maxerr = input('Enter Maximum Error: ');

xn = (xn_2*f(xn_1) - xn_1*f(xn_2))/(f(xn_1) - f(xn_2));

disp('xn-2              f(xn-2)                 xn-1              f(xn-1)               xn              f(xn)');
disp(num2str([xn_2 f(xn_2) xn_1 f(xn_1) xn f(xn)],'%20.7f'));
flag = 1;
while abs(f(xn)) > maxerr
    xn_2 = xn_1;
    xn_1 = xn;
    xn = (xn_2*f(xn_1) - xn_1*f(xn_2))/(f(xn_1) - f(xn_2));

    disp(num2str([xn_2 f(xn_2) xn_1 f(xn_1) xn f(xn)],'%20.7f'));

    flag = flag + 1;

    if(flag == maxiter)
        break;
    end
end

if flag < maxiter
    display(['Root is x = ' num2str(xn)]);
else
    display('Root does not exist');
end