how to calculate by tol and while loop

k0=(2*pi/0.6328)*1e6;
t2=1.5e-6;
n1=1.512;n2=1.521;
x=2; % approximation

k1=k0*sqrt(n1^2-x.^2);k2=k0*sqrt(n2^2-x.^2);

tol = 1e-12; 
n = 1;
while (n<=200)
    y =-(k2).*t2+atan(k1./1i*k2)
    if abs(ynew-y) < tol, break; end
    x =xnew;
    k1=k0*sqrt(n1^2-x.^2);
    k2=k0*sqrt(n2^2-x.^2);
    
    n=n+1;
end
disp(xnew)

how to use while loop in this program and f(abs ) value use

Answer 1

[Voss]

Your while loop might have a structure like this:

tol = 1e-12;
err = Inf;
n = 1;
while n <= 200 && err > tol
    % get new estimate (of whatever you are trying to calculate)
    % calculate updated error, err
    n = n+1;
end
disp(n)

   201

[shiv gaur]

k0=(2*pi/0.6328)*1e6;

t2=1.5e-6;
n1=1.512;n2=1.521
k1=k0*sqrt(n1^2-x^2);
k2=k0*sqrt(n2^2-x^2);
y=-(k2)*t2+atan(k1/1i*k2)

sir we have to find the value of x from k1,k2 ,y equation so I am not able

so pl apply this in program