✔ 最佳答案
(a) g(-x) = f(-x) + f(x) = g(x) and so g(x) is an even function
(b) h(-x) = f(-x) - f(x) = -[f(x) - f(-x)] = -h(x) and so h(x) is an odd function
(c)(i) f(x) = a^x
g(x) = a^x + 1/a^x , h(x) = a^x - 1/a^x
(ii) f(x) = (1 + x)^n
g(x) = (1 + x)^n + 1/(1 + x)^n
h(x) = (1 + x)^n - 1/(1 + x)^n