function P = leastSquaresApproxDFT(x,c,d,m)
n=length(x);
y=DFT(x);
a=real(y);
b=imag(y);

syms q;

P= a(1)/sqrt(n);

for k=1:m/2-1
    P= P + (2/sqrt(n))*(a(k+1)*cos(2*pi*k*(q-c)/(d-c))-b(k+1)*sin(2*pi*k*(q-c)/(d-c)));
end

P= P + (2*a((m/2)+1)/sqrt(n))*cos(n*pi*(q-c)/(d-c));
P= matlabFunction(P);