How to plot an Explicit function with inseparable

I am trying to plot this funtion shown below. I cannot separate the funtion and have P_bar in terms of I_bar to plot the graph. In the equation P is a not a variable and is set at 5000.

I want to rearrange the formulae so that P_bar is in terms of I_bar or vice versa so that I can plot it.

I have tried the below but I am only solving the two equactions at the point where they are equal to each other.

1- syms ibar pbar

2- eqnLeft = 2+(2*ibar/pbar)^2-(4*ibar/1000)*sin(2*ibar/pbar)-2*cos(2*ibar/pbar) - (2*ibar/pbar^2)^2;

3- eqnRight = tan((2*ibar/pbar)*(1-1/2*pbar))- 2*ibar/pbar);

4- fplot([eqnLeft eqnRight])

5- title([texlabel(eqnLeft) ' = ' texlabel(eqnRight)])

Answer 1

[Alan Stevens]

having set values of Ibar you could find Pbar using function fzero. Like so:

Ibar = 1:0.001:2;
pbar = zeros(1,numel(Ibar));

Pbar0 = 1;
for i = 1:numel(Ibar)
pbar(i) = fzero(@Pfn,Pbar0,[],Ibar(i));
end

plot(Ibar,pbar),grid
xlabel('Ibar'),ylabel('Pbar')

function F = Pfn(Pbar,Ibar)
          
         P = 5000;
         r = 2*Ibar/Pbar;
         if Ibar<=1.166
            F = (r/Pbar)^2 - 2 - r^2 + (4*Ibar/P)*sin(r) + 2*cos(r);
         else
             F = r - tan(r*(1-1/(2*Pbar)));
         end    
         
end