pi -------------- / 2 2\ | pi *x | 3*|1 + ------| \ 9 /
pi/((3*(1 + (pi^2*x^2)/9)))
3*pi ---------- 2 2 9 + pi *x
3*pi/(9 + pi^2*x^2)
3.14159265358979/(3.0 + 3.28986813369645*x^2)
pi ---------- 2 2 pi *x 3 + ------ 3
pi/(3 + pi^2*x^2/3)
9*pi ------------- 2 2 27 + 3*pi *x
9*pi/(27 + 3*pi^2*x^2)