Using the known geometric series representation
=
x
n, valid for -1 < x < 1, find a power series representation for f(x) = tan
-1(2x) in powers of x. On what interval does the series converge to f(x)?
◦ f(x) =
, for -
< x ≤
◦ f(x) =
, for -
≤ x ≤
◦ f(x) =
2n + 1, for - 2 ≤ x ≤ 2
◦ f(x) =
, for -
< x <
◦ f(x) =
2n + 1, for - 2 < x < 2