how to solve equation

V*sqrt(1-b)=m*pi+atan(b/1-b)+atan(a+b/1-b)
% where ns=1.40;
nc=1.45;
nf=1.5;
% where a=(ns^2-nc^2)/(nf^2-ns^2)
b=(neff^2-ns^2)/(nf^2-ns^2)
% by varying V=1:10
plot(V,neff)

[shiv gaur]

not working

[Fabio Freschi]

I assume you want to find the value of neff that solve the equation. However, I think that you are misprinting your initial function:

V*sqrt(1-b)=m*pi+atan(b/1-b)+atan(a+b/1-b)

Because it is useless to divide b by 1. Could you report correctly the function you want to solve, with the values of all parameters?