How to plot data using the sigmoid and hyperbolic tangent functions.

Hello forums;

I am trying to write a MATLAB script to plot some data using a sigmoid and hyperbolic tangent function. I have been researching for so long but to no avail. If somebody could help that would be amazing! The data file and the equations are below. I have some code that has worked somewhat but it is mainly the last function I am struggling with. Anything helps!

Answer 1

[David Hill]

Here is your code with a few corrections.

x = xlsread('Lab 4 Data.xlsx','A2:A47')/1000;
f = xlsread('Lab 4 Data.xlsx','B2:B47')/1000; 
n = length(x);
g_1 = 1; 
g_2 = 1./(1+exp(-1*x));
g_1 = ones(size(x)); 
G=[g_1,g_2];


transG=transpose(G);

RHS=transG*f;
LHS=transG*G;
c=linsolve(LHS,RHS);

g_x=c(1)+c(2)*(1./(1+exp(-1*x)));


r=g_x-f;
R=sum(r.^2);

figure
plot(x,g_x) 
hold on
plot(x,f,"*") 
legend('g(x)','f data') 
title('Lab 4 sigmoid Fit') 
ylim([.0024 .0036]) 
xlim([-.2 3.5]) 
ft=@(x)(exp(x)-exp(-x))./(exp(x)+exp(-x));%here is the equation for hyperbolic tangent function
hold off;

plot(x,ft(x));

[Dawson Duran]

I try to implement the hyperbolic tangent function but it keeps failing to yeild the same results. Could you show your code for obtaining the second graph? I have tried swapping formulas and editing to apply it but it doesn't seem to work.

[David Hill]

x = xlsread('Lab 4 Data.xlsx','A2:A47')/1000;
ft=@(x)(exp(x)-exp(-x))./(exp(x)+exp(-x));
plot(x,ft(x));