(1)
g(x) = f(x) + f(-x)
g(-x)
= f(-x) + f(x)
= g(x)
所以 g(x) = f(x) + f(-x)是偶函数
(2)
h(x) = f(x) - f(-x)
h(-x)
= f(-x) - f(x)
= -h(x)
所以h(x) = f(x) - f(-x)是奇函数
(1)
g(x) = f(x) + f(-x)
g(-x)
= f(-x) + f(x)
= g(x)
所以 g(x) = f(x) + f(-x)是偶函数
(2)
h(x) = f(x) - f(-x)
h(-x)
= f(-x) - f(x)
= -h(x)
所以h(x) = f(x) - f(-x)是奇函数