% Problem Set #1 - Problem 5

t=-1:.001:2;
x = 5*exp(-2*t) .*cos(20*pi*t) .* (t>=0);
plot(t,x);
xlabel('t');
ylabel('x');   
title('Problem 5');




% Problem Set #1 - Problem 6

n=-1:10;
x = (-0.8).^n .* (n >=0);
stem(n,x);
xlabel('n');
ylabel('x');
axis([-2 10 -1 1]);
title('Problem 6');