全 国
山东省
陕西省
西藏自治区
面积(万平方千米)
960
15
19
120
人口(万)
133972
9579
3732
300
人口密度(人/平方千米)
139.5
638
196
2.5
A:人口增长速度快
B:人口分布疏密不均
C:人口与资源矛盾突出
D:少数民族人口所占比例少
已知t>0,设函数f(x)=x3﹣3t+12x2+3tx+1.
(Ⅰ)若f(x)在(0,2)上无极值,求t的值;
(Ⅱ)若存在x0∈(0,2),使得f(x0)是f(x)在0,2上的最大值,求t的取值范围;
(Ⅲ)若f(x)≤xex﹣m+2(e为自然对数的底数)对任意x∈0,+∞)恒成立时m的最大值为1,求t的取
值范围.
My name is Chen Lan. My home is in Gulangyu. Do you know it? It is in Xiamen. It is near the sea(海). Gulangyu is a small place,but it is very nice and clean. There are no cars,no buses. People only walk. So it is very quiet. Our house is in the middle of Gulangyu. Behind our house there is a big old tree. My grandfather tells me that the tree is very,very old. There are many birds in the tree. We call it a “bird tree”. Our house is near the sea. The sea is big and blue. There are a lot of fish in the sea. After school,I go there and catch(捉) fish with my friends. It is very interesting. I like fish and I like catching fish.