Falsi method algorithm - matlab

Question

I wrote a falsi method code and I got problem with fa function. My general function is in interval [a,b]=[2,12], as I defined in main script:
a=2;
b=12;
%Function
syms x real;
f=1.2*sin(x)+2*log(x+2)-5;
I wonder how to correctly pass argument a to the function fa and, in general, to falsi method function . I guess, it cannot be just '2', it must be dynamic somehow. Thanks for tips ! :)
function [ x ] = task1_falsi( f, x, a)
% Defining functions
a=2;
fa=feval(f,a);
f=inline(f);
fa=inline(fa);
err=1;
% Falsi's loop.
% Stops when error is negligible or number of iterations becomes prohibitive
it=0;
while (it<1000) && (err>10e-5)
% Falsi's algorithm
x1=x-feval(f,x)*(x-a)/fa;
% Calculating error
err=abs(x1-x);
% New zero is previous value
x=x1;
it=it+1;
%Showing steps
fprintf('%d\t%f \n',it, x);
end
disp('Root:');
disp(x);
disp('Iterations:');
disp(it);
end

Answer 1

%Task 1
% Falsi's method algorithm
function [ x ] = task1_falsi( f, x)
err=1;
y = 7; % Starting point
z = 8;
f=inline(f);
% Ending point
maxIteration = 1000; % Maximum number of iterations
epsilon = 0.001; % Accuracy
it=0; % Vector with number of iterations
xold = z; % Variable used for calculations
solutionRegulaFalsix=zeros(10,1); % Error vector
for j=0:20
while (it <= maxIteration)
x1 = y - ((feval(f,y)*(z-y))/(feval(f,z)-feval(f,y))); % Calculating the root
it= it+ 1;
if (abs(x1-xold)<epsilon*abs(x1)) % Accuracy condition
break;
else
xold = x1;
if feval(f,y)*feval(f,z) > 0
y = x1; % Starting point is being changed
else
z = x1; % Ending point is being changed
end
end
end
err = abs(x1-x); % Calculating the error
% epsilon = epsilon/10;
%Showing steps
fprintf('%d\t%f \n',it, x);
y=2;
z=3;
disp('Root:');
disp(x1);
disp('Iterations:');
disp(it);
end
end