clear all;

x = [1,2,3,4,5,6,7,6,5,4,3,2,1];
n = -2:10;

[x1,n] = sigshift(x,n,5); 
[x2,n] = sigshift(x,n,-4);
[s,n] = sigadd(2*x1,n,-3*x2,n);

stem(n,s);
title('sequence in part a');
xlabel('n');
ylabel('x(n)');
