if (exist("n")==0 || n<0) n=0 n=n+1 f(x,n)= pi/2 - sum[m=1:n] 4.0/pi/(2*m-1)**2*cos((2*m-1)*x) unset label set label sprintf("max k = %d", 2*n-1) at -3.8, -0.5 plot f(x,n) if(n<5) reread