Anyone know how I can improve my code and create the following equation? I only have the signal and image toolboxes

%*************************************************************************
%%This fucntion will store transducer coordinates and differences of
%%arrival times between each transducer and transducer 1
% which are aquired via graphData() and store them in the 2D
%%non-linear function 
%**************************************************************************

function equation(xti,yti,zti,deltai,v)%known values are input parameters

    b = ?;
    a = (xti - xs)^2;
    b = (yti - ys)^2;
    c = (zti - zs)^2;
    d =(ts - deltai);
    e = a + b + c;
    f = sqrt(e);
    g = f/v;
    i = g - d;
end

[darova]

Looks ok. What doesn't work?

[Timothy Nsubuga]

It says invalid expression check for missing characters but before it wanted me to define the xs,ys,zs and ts but those are unkowns I want to solve for.

[per isakson]

See Symbolic Math Toolbox

[Timothy Nsubuga]

Then I can't create this equation without the toolbox?

[per isakson]

You can solve it numerically, see fsolve Solve system of nonlinear equations and possibly Code to run script multiple times, but it's a bit noisy.