Problem:

`syms w; % variable, that define the y axis`

lam = 4*pi()^2 % constant, that define the x axis

tan(w/2) == w/2 - (4/(lam))*(w/2)^3 % equation

That equation with that constant has many solutions. What I pretend is to resolve the equation (maybe with solve) for lam = 4*pi()^2, in a certain interval of y, in order to catch a specific solution. For example, I know that for that constant there is a solution of w/pi() = 2 in the interval w/pi()=[1.5 2.5], (y axis).

I was trying with this:

`syms w;lam=4.*pi().^2;x = fsolve(@(w) tan(w/2) == w/2 - (4./(lam)).*(w/2).^3, [1.5*pi() 2.5*pi()]);X=x/pi()`

But is giving me some problems that I canĀ“t resolve.

On Maple software the structure of the program is more or less the same, but it gives me the solutions that I want in specific intervals of y axis.

Matlab has to do it too or it doesn't?

Thanks to all.

## Best Answer