Hi, I have a problem in MATLAB. I am doing research in Optics ... I have to find 4 values from 5 equations and having some trouble. Kindly help.

I have tried reg this as below: I would be grateful to have any suggestions. Thanks in advance.

clear

T = 0.89;
R = 0.11;
lamda = 0.98;
d = 1.65;
pi = 3.14;
phit = 0.6;
phir = 0.31;
%((-(a))*d) == (23.03)*k;

% sym a b n k; % a and b are "alpha" and "beta"

a = sym('a');
b = sym('b');
n = sym('n');
k = sym('k');

eq1 = T == '({(1-R)^2+4*R*(sin(phir))^2}*exp((-a)*d))/((1-R*exp((-a)*d))^2+4*R*exp((-a)*d)*(sin(b+phir))^2)';
eq2 = (phit) == '((2*(pi)*n*d)/lamda)-(atan((k(n^2+k^2-1))/((k^2+n^2)*(2+n)*n)))+(atan((R*exp((-a)*d))*(sin2(b+phir))/(1-R*exp((-a)*d)*cos2(b+phir))))';
eq3 = (phir) == 'atan(((-2)*k)/(1-((n)^2)-((k)^2)))';
eq4 = (b) == '((2*(pi)*n*d)/lamda)';
eq5 = (a) == '((4*(pi)*k)/lamda)';
%eq6 = (e) == '((-(a))*d) == (23.03)*k';

[a b n k] = solve(eq1,eq2,eq3,eq4,eq5,a,b,n,k);