/ ___\ atan\5*\/ x /
atan(5*sqrt(x))
5 ------------------ ___ 2*\/ x *(1 + 25*x)
/1 50 \ -5*|- + --------| \x 1 + 25*x/ ------------------ ___ 4*\/ x *(1 + 25*x)
/ 625 3 25 \ 5*|----------- + ---- + --------------| | 2 2 2*x*(1 + 25*x)| \(1 + 25*x) 8*x / --------------------------------------- ___ \/ x *(1 + 25*x)