See if this does what you want:
F=96485;
T=298;
R=8.314;
% % % i=a*exp(-c*F*E/(R*T))+b*exp(-d*F*E/(R*T)); % Original Equation
% % % a = p(1), b = p(2), c = p(3), d = p(4) % Define Parameters
fcn = @(p,E,i) p(1).*exp(-p(3)*F*E/(R*T)) + p(2).*exp(-p(4)*F*E/(R*T)) - i;
E = 42; % Use Correct Value
i = 24; % Use Correct Value
p0 = rand(4,1)*1E-6;
[Params,fval] = fsolve(@(p)fcn(p,E,i), p0)
If you have vectors of values for ‘E’ and ‘i’, use a nested loop to iterate through them:
E = [...];
i = [...];
for k1 = 1:numel(E)
for k2 = 1:numel(i);
Params{k1,k2} = fsolve(@(p)fcn(p,E(k1),i(k2)), p0);
end
end
