下列四个命题：（1）函数f（x）在[0，+∞）上是增函数，在（﹣∞，0）上也是增函数，所以f（x）在R上是增函数；（2）若函数f（x）=ax2+bx+2与x轴没有交点，则b2﹣8a＜0，且a＞0；（

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下列四个命题：（1）函数f（x）在[0，+∞）上是增函数，在（﹣∞，0）上也是增函数，所以f（x）在R上是增函数；（2）若函数f（x）=ax²+bx+2与x轴没有交点，则b²﹣8a＜0，且a＞0；（3）y=x²﹣2|x|﹣3的递增区间为[1，+∞）；（4）函数y=lg10^x和函数y=e^lnx表示相同函数．其中正确命题的个数是（）

A：3

B：2

C：1

D：0

上一题下一题 0.0难度选择题更新时间:2015-07-01 05:27:51

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D

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根据短文理解，完成各题任务。
C
    Sally is an English girl. She is my English teacher, Mrs. Brown's daughter. She is only five years old. (A)She can't go to school. She likes playing ping-pong.
    Her favorite ping-pong player is Zhang Yining. Sally is in the ping-pong club. She goes to the ping-pong club every day. She plays ping-pong for two hours there.
    Sally has a sister. Her name is Maria. She is in our class. She likes running. She runs with her mother every morning. (B)她最喜欢的赛跑明星是刘翔. Maria says she wants to be a running star like Liu Xiang.

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