Step-by-step explanation:
arctan(x) is less than π/2 for x > 0. Therefore, if we say g(x) = 13 (π/2) / eˣ, then f(x) < g(x) for all values of x > 0.
g(x) = 13 (π/2) / eˣ
g(x) = 13π/2 · (1/e)ˣ
So g(x) is a geometric series where r = 1/e. Since |r| < 1, the series converges.
Since g(x) converges, the smaller f(x) also converges.
