25.已知函數(shù)
,其中m∈R.
(1)當(dāng)函數(shù)f(x)為偶函數(shù)時(shí),求m的值;
(2)若m=0,函數(shù)
,是否存在實(shí)數(shù)k,使得g(x)的最小值為0?若存在,求出k的值,若不存在,說明理由;
(3)設(shè)函數(shù)
,若對(duì)每一個(gè)不小于2的實(shí)數(shù)x
1,都有小于2的實(shí)數(shù)x
2,使得q(x
1)=q(x
2)成立,求實(shí)數(shù)m的取值范圍.