I'm getting Not enough input arguments

function [val] = S_inf (V, theta)

k = 2;

val = 1./(1+exp(-(V-theta)./k));

end

x = S_inf(10, -44);

Answer 1

[madhan ravi]

Your last line should be before the function

[madhan ravi]

 x = S_inf(10, -44);

 function [val] = S_inf (V, theta) % saved in a separate file named S_inf.m if your using version prior to 2016b
         k = 2;
         val = 1./(1+exp(-(V-theta)./k));
 end