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问题 判断题

内摩擦力是产生流体阻力的根本原因。

答案

参考答案：对

解答题
已知函数f（x）=x2+2|lnx-1|．
（1）求函数y=f（x）的最小值；
（2）证明：对任意x∈[1，+∞），lnx≥
2(x-1)
x+1
恒成立；
（3）对于函数f（x）图象上的不同两点A（x1，y1），B（x2，y2）（x1＜x2），如果在函数f（x）图象上存在点M（x0，y0）（其中x0∈（x1，x2））使得点M处的切线l∥AB，则称直线AB存在“伴侣切线”．特别地，当x0=
x1+x2
2
时，又称直线AB存在“中值伴侣切线”．试问：当x≥e时，对于函数f（x）图象上不同两点A、B，直线AB是否存在“中值伴侣切线”？证明你的结论．
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单项选择题

The mother of a 1B-year-old girl calls the emergency department, suspecting her daughter's abdominal pain may be appendicitis. In addition to pain, her daughter has a fever of 100°F (37.8℃) and has vomited twice. What should the nurse tell the mother ？（）

A．Give the daughter a laxative to rule out the possibility that constipation is causing the pain.

B．Gently press on the left lower quadrant of her daughter's abdomen to test for rebound tenderness.

C．It's most likely the flu because her daughter is too young to have appendicitis.

D．Immediately bring her daughter into the emergency department before the appendix has a chance to rupture.
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