Question

4. verify the following identities 0 (a) 1 = 10 (x) + 2 (-1)"l2n(x) n=1 00 (b) e* = 10(x) +2 1. (x) = n=1 0 c) (c) e-* = 10(x) +2X(-1)"In(x) -X = n=1 0 (d) cosh x = 10(x) +2 Izn (x) X d n=1 00 (e) sinh x = 222n-1(x) - n=1