Question1: One of your friends is usually exhausted for his work. What suggestions will you give to him if he wants to cultivate some personal interests?
【简答题】设函数 f(x)=-co s 2 x-4t?sin x 2 cos x 2 +2 t 2 -6t+2(x∈R) (1)当t=1时,求f(x)的最小值; (2)若t∈R,将f(x)的最小值记为g(t),求g(t)的表达式; (3)当-1≤t≤1时,关于t的方程g(t)=kt有且只有一个实根,求实数k的取值范围.