有一类计算题,已知函数f(x),求这个函数f(x)在许多点处的函数值之和.对这类计算题,往往直接计算甚是繁杂,费时费力,但根据已知函数f(x)的特点,通过两两配对,而恰恰每一对的和又是定值,这时,可巧妙地解决问题,下面举例说明.【例1】如果函数f(x)=1+x2x2,则f(1)+f(2)+…f(9)+f(21) There is a type of calculation problem, known as the function f(x), and the sum of the function values ​​of this function f(x) at many points. For such calculation problems, it is often straightforward to calculate and it is cumbersome and time-consuming, but according to the known The characteristics of the function f(x) are paired with each other, and exactly the sum of each pair is a fixed value. In this case, the problem can be subtly solved. The following is an example. [Example 1] If the function f(x)=1 +x2x2, then f(1)+f(2)+...f(9)+f(21)