Confused on this problem

I am trying to figure out how to do it but I am confused in writing it.

Attach is my scripts

[matthew choo]

%Describe clearly how the N-point DFT performed on a signal defined

%x[n]=sin(2*pi*n/100)

%for 0=<n=<100

%for x[n]=0 for n>100

%N=100

%N=1000

N0=100;

n=0:1/50/N0:1/50-1/50/N0;

x_n=sin((2*pi*n)/100)

x_DFT=fft(x_n)

x_CTFS=1/N0*[x_DFT(4)/2,x_DFT(5:6),x_DFT(1),x_DFT(2:3),x_DFT(4)/2]

t=0:1/50/100:1/50;

x_t1=sin((2*pi*n)/100);

x_t2=0;

for nn=-N0/2:N0/2;

x_t2 = x_t2+x_CTFS(nn+N0/2+1)*exp(j*(nn)*2*pi*50*t);

end

figure(1),subplot(2,1,1),plot(t,x_t1) %original x(t)

title('f_s=f_{Nyq}'),xlabel('t'),ylabel('x(t) and x(n)'), hold on

subplot(2,1,1),stem(n,x_n,'fill'),hold off %samples x(n)

figure(1),subplot(2,1,2),plot(t,x_t2) %CTFS representation of the signal

xlabel('t'),ylabel('x(t) from CTFS'),