How many of the following functions are even [sin x is odd and cosx is even]
(a) f(x) = x2|x| (b) f(x) = ex+e−x
(c) f(x) = log[1−x1+x] (d) log(√x2+1- x)
(e) f(x) = log(x + √x2+1 (f) ax−a−x
(g) f(x) = sinx+cosx (h) sinx×(ex−e−x)