___ \/ x - atan(2*x + 1)
sqrt(x) - atan(2*x + 1)
1 2 ------- - -------------- ___ 2 2*\/ x 1 + (2*x + 1)
1 8*(1 + 2*x) - ------ + ----------------- 3/2 2 4*x / 2\ \1 + (1 + 2*x) /
2 16 3 64*(1 + 2*x) ----------------- + ------ - ----------------- 2 5/2 3 / 2\ 8*x / 2\ \1 + (1 + 2*x) / \1 + (1 + 2*x) /