>    # CESARO SUMMATION OF A TRIANGLE WAVE

>   

>    aodd := k -> 1/(2*k + 1)^2;

aodd := {k}  -> 1/((2*k+1)^2)

>    partialsum := K -> (Pi/2) - (4/Pi)*sum(aodd(k)*cos((2*k+1)*x), k=0..K);

partialsum := {K}  -> 1/2*Pi-4/Pi*sum(aodd(k)*cos((2*k+1)*x),k = 0 .. K)

>    mean := M -> (1/(M+1))*sum(partialsum(K), K=0..M);

mean := {M}  -> 1/(M+1)*sum(partialsum(K),K = 0 .. M)

>    plot([partialsum(1), mean(1)], x=-1..7);

[Maple Plot]

>    plot([partialsum(5), mean(5)], x=-1..7);

[Maple Plot]

>    plot([partialsum(20), mean(20)], x=-1..7);

[Maple Plot]

>    # Close inspection shows that the Cesaro mean curve is BLUNTER than the partial sum curve.

>    # When the partial sums are already well convergent, Cesaro summation just slows down the convergence.

>    # This is shown clearly by examining the error in the approximations:

>   

>    plot([abs(x) - partialsum(5), abs(x) - mean(5)], x=0..1);

[Maple Plot]

>    plot([abs(x) - partialsum(10), abs(x) - mean(10)], x=0..1);

[Maple Plot]

>