问题
填空题
函数f(x)=(1-
|
答案
：∵f(x)=(1-
)ex(x＞0)a x
∴f'（x）=（
-a x2
+1）exa x
∵函数f（x）既有极大值又有极小值
∴f'（x）=（
-a x2
+1）ex=0有2个不等实数根a x
∴x2-ax+a=0有2个不等的正实数根
∴△=a2-4a＞0且a＞0
∴a＞4
故答案为a＞4
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函数f(x)=(1-
|
：∵f(x)=(1-
)ex(x＞0)a x
∴f'（x）=（
-a x2
+1）exa x
∵函数f（x）既有极大值又有极小值
∴f'（x）=（
-a x2
+1）ex=0有2个不等实数根a x
∴x2-ax+a=0有2个不等的正实数根
∴△=a2-4a＞0且a＞0
∴a＞4
故答案为a＞4
选择下列词汇或短语完成下面对话。
B: Not yet. Is there anything new? A: It says that four Chinese girl students will stand for Chinese law students to 小题2: Harvard University for lawyer competition. B: Oh yes! I’ve heard that on the radio. The four girls are 小题3: Shenzhen. They are very excellent. A: Yes, I feel really 小题4: of them. B: Me, too. I will pay 小题5:attention to their next competition. |