【题文】方程的解集是( )A.{3}B.{-1}C.{-1,3}D.{1,3}
题型:难度:来源:
【题文】方程
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324191418-77888.png)
的解集是( )
A.{3} | B.{-1} | C.{-1,3} | D.{1,3} |
答案
【答案】A
解析
【解析】本题考查对数的含义,方程的解法,同解变形的能力.
要使方程有解,需使
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324191418-49909.png)
所以
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324191418-93000.png)
在
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324191419-28055.png)
时可原方程可化为
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324191419-95867.png)
,即
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324191419-13198.png)
解得
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324191419-89102.png)
(舍去).
故选A
举一反三
【题文】函数
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324191410-10273.gif)
满足条件
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324191410-47742.gif)
,则
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324191411-61720.gif)
的值为( )
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324191411-86914.gif)
.5
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324191411-21597.gif)
.6
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324191411-88863.gif)
.8
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324191411-64689.gif)
.与
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324191412-64420.gif)
,
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324191412-65390.gif)
值有关
【题文】
设函数
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324191400-17833.gif)
是定义在
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324191400-22300.gif)
上的函数,且对于任意的
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324191401-79179.gif)
,有
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324191401-17534.gif)
,
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324191401-81754.gif)
,若
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324191401-46735.gif)
,则
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324191401-91220.gif)
( )
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324191402-17701.gif)
.
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324191402-78728.gif)
.
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324191403-86626.gif)
.
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324191404-47721.gif)
.
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324191404-31171.gif)
【题文】(本题满分14分)
把下列各式分解因式
(1)
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324191357-65001.gif)
(2)
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324191357-30451.gif)
【题文】若函数
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324191353-27199.png)
的值域是其定义域的子集,那么
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324191353-27199.png)
叫做“集中函数”,则下列函数:
①
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324191353-31892.png)
, ②
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324191353-60607.png)
③
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324191354-10195.png)
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324191354-37840.png)
, ④
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324191354-95703.png)
可以称为“集中函数”的是
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324191354-93742.png)
(请把符合
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324191354-71973.png)
条件的序号全部填在横线上)
【题文】下列四组函数,w.w.w.k.s.5 u.c.o.m表示同一函数的是
最新试题
热门考点