Given the function ,
(I) Find the minimum value of the function ;
(II) Let , proposition : The inequality holds for any ; proposition : The exponential function is increasing. If "p or q" is true, and "p and q" is false, find the range of the real number .
Problem 245
Official solution
Solution:
(I) Given ,
For , according to the graph and properties of the root function,
we have: when , the function reaches its minimum value of 1,
For , the function is decreasing,
when , the function reaches its minimum value of 1,
Overall, the minimum value of the function is .
(II) From (I), we have holds for any
which means , solving this gives ,
Therefore, for proposition : .
For proposition : The exponential function is increasing,
thus ,
Therefore, for proposition : .
If "p or q" is true, and "p and q" is false,
then , are true and false respectively,
Considering two cases:
If is true and is false, then , solving this gives .
If is false and is true, then , solving this gives .
Therefore, the range of the real number is , which can be summarized as .