MATLAB: How to sketch x[n] = 2e^(n.j.pi/6) +2e^(-n.j.pi/6) for 0

complex-valued exponential signal

I am relay knew to MATLAB and need to do this for an assignment. Any help would be appreciated.

Something like this?

syms x(n)
x(n)=piecewise(n>0 & n<5,2*exp(n*j*pi/6)+2*exp(-n*j*pi/6),0)
n=0:0.001:5;
plot(n,x(n))

Replace your code with:

summ=0;  
for j=1:n
  summ=sum(A,2)
end

so there is no confusion between the variable summ and the function sum.

You can create three nested loops for i, j and k. and check for your condition:

if ((A(i,j)<=B(k,j) && (A(i,j)>B(k-1,j))

Take care that, when k=1, you cant check both the conditions and only the first conditions is to be applied.

Hope it helps.