clear all;

n = 0:20;
x1 = n.*(stepseq(0,0,20)-stepseq(10,0,20));
x2 = 10*exp(-0.3*(n-10)).*(stepseq(10,0,20)-stepseq(20,0,20));
x = x1 - x2;
stem(n,x,'filled');
title('sequence in part b');
xlabel('n');
ylabel('x(n)');