因为f(x)是一元二次函数所以设 f(x) = ax² + bx + c ( a ≠ 0)因为f(x + 1) = f( x ) + x + 1a(x + 1)² + b(x + 1) + c = ax² + bx + c + x + 12ax + a + b = x + 1所以 2a = 1 ,a + b = 1所以 a = 1...a(x + 1)² + b(x + 1) + c = ax² + bx + c + x + 1什么意思阿？？？等号左边就是 f(x + 1) ，右边是 f(x) + x + 1