函数y=-x2-4x+1,x∈[-3,2]的值域( ) A. (-∞,5) B. [5,+∞) C. [-11,5] D. [4,5] 答案:C 【解析】 ∵,函数图象的对称轴为, ∴当时,函数单调递增;当时,函数单调递减. ∴当时,函数有最大值,且最大值为. 又当时,;当时,. ∴. 故函数的值域为.选C. 点睛:求二次函数在闭区间上最值的类型及解法 二次函数在闭区间上的最值主要有三种类型:轴定区间定、轴动区间定、轴4.听第9段材料,回答第13至16题.13.What time is it now?A.3:00.B.3:30.C.4:30.14.Who are Mrs White and his son going to see?A.Tony's grandpa.B.Tony's father.C.Tony's grandma.15.What does the woman think of Tony?A.He is slow.B.H e is early.C.He is cute.16.Where does the dialogue take place?A.At the railway station.B.At the entrance to the airport.C.On the way to the bus stop.