f' (2) = 4(ln2---1)
2ln2- 1, f''(2) =                2
12ln2---4(ln-2)---6-
    (2ln2 - 1)3, -1
R =                   2
---12-ln2---4(ln2)----6---
[20(ln2)2 - 36 ln 2 + 17]3/2.