close all
clear all 
clc

t = -10:.1:10;
a = 2;
b = 6;
figure
plot(t,tanh(t),...
     t,tanh(a*t),t,tanh(t/a),...
     t,tanh(a*t-b),t,tanh(a*t+b),...
     t,tanh((t-b)/a),t,tanh((t+b)/a))
grid on
xlabel('time [s]')
ylabel('signal')
legend('tanh(t)','tanh(at)','tanh(t/a)',...
    'tanh(at-b)','tanh(at+b)',...
    'tanh((t-b)/a)','tanh((t+b)/a)')
title('tanh and its shifted/scaled versions')

% printing figure in png format
set(gcf,'PaperUnits','inches','PaperPosition',[0 0 4 3])
print -dpng homework1.png -r100