I have tried solving DFT but i am getting an error

Here is my code: i tried solving using matrix multiplication

   f1=7;f2=21;
fs=220; %Sampling frequency f2*10
ts=1/fs; %sampling time
t=0:10-ts; 
y=sin(2*pi*t*f1)+sin(2*pi*t*f2); %given data set
N=length(y);
n = 0:1:N-1; % row vector for n
k = 0:1:N-1; % row vecor for k
WN = exp(-1j*2*pi/N); % the w elements
n1= transpose(n);
nk = n1*k; % creates a N by N matrix of nk values
WNnk = WN .^ nk; % DFT matrix
Xk = WNnk.*y;
plot(n,xk)

Here is my error message:

Error using .* Matrix dimensions must agree.

Error in a21 (line 13) Xk = WNnk.*y;

Please help me plot:

[Walter Roberson]

At the time of your line WNnk.*y then WNnk is 10 x 10 and y is 1 x 10. What size of output were you expecting from that?

Note: your line

t=0:10-ts;

should be

t=0:ts:10-ts;