Assignment:
Recall that S_N (f)(x)= sum (n=-N to N) c_n e^{inx}= 1/2pi integral (from -pi to pi) f(x-t)sin ((N+1/2)t)/sin(t/2) dt
Prove that if f in R[-pi, pi] and integral (from -1 to 1) |f(t)/t)|dt < infinity (convergent) then lim( as N goes to infinity) S_N(f)(0)=0
Hint: Use the Riemann-Lebesgue lemma.