2f(x) + f(-x) = 3x + 2 ①
2f(-x) + f(x) = -3x + 2 ②
①式 × 2 - ②式 得:
3f(x) = 9x + 2
f(x) = 3x + 2/3
所以 f(2) = 3 × 2 + 2/3 = 20/3
2f(x) + f(-x) = 3x + 2 ①
2f(-x) + f(x) = -3x + 2 ②
①式 × 2 - ②式 得:
3f(x) = 9x + 2
f(x) = 3x + 2/3
所以 f(2) = 3 × 2 + 2/3 = 20/3