A、<img width="144" height="21" src="http://admintk.100xuexi.com/UpLoadImage/2016-10-26/48cd3949-8836-4d06-9626-2b058fec457c.png" />
B、<img width="153" height="21" src="http://admintk.100xuexi.com/UpLoadImage/2016-10-26/60ba1a9e-9b34-4de2-89da-c05f9cbdb0bb.png" />
C、<img width="147" height="24" src="http://admintk.100xuexi.com/UpLoadImage/2016-10-26/672c7e01-8512-4bb5-a370-44e2dc4cd4ac.png" />
D、<img width="111" height="24" src="http://admintk.100xuexi.com/UpLoadImage/2016-10-26/ce56d473-81c1-49ad-8fdf-2a9c361b4e51.png" />
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，则对任何实数
，都有（ ）。