We want to define an error function $E(x)=|f(x)-S_N(x)|$ where $S_n$ for the partial sums of the Fourier series of the above function for N=7,14,20. (We have done it already). My question is how to calculate its values at the points of a 10-point partition of the base interval $[-L,L]$ using the Table and Tableform commands.
