2. The function $f(x)=x^{2}-t x+2$ has an inverse function on $[-1,2]$. Then the range of all possible values of the real number $t$ is $\qquad$ .
$$
\text { 2. }(-\infty,-2] \cup[4,+\infty) \text {. }
$$

According to the given conditions, the axis of symmetry is $\frac{t}{2} \notin(-1,2)$.