For my algorithm analysis course, I've derived from an algorithm the function f(n) = n^2 - n + 2. Now I need to prove or disprove **f(n) ? O(n)**. Obviously it's not, so I've been trying to disprove that for a few hours and can't figure out how to do it.

To disprove it, I need to prove the negative:

```
?M > 0, ?N > 0, ?n > N s.t. n^2 - n + 1 < M·n
```

I've tried working backwards and forwards, but can't seem to get anywhere. I've also tried to prove that, against my judgment, f(n) ? O(n):

```
?M > 0, ?N > 0 s.t. ?n > N, n^2 - n + 1 ? M·n
```

... with no success. What am I doing so horribly wrong?