1 . 设a,b,c均为大于零的实数,若一元二次方程
有实根,则( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/13fa32c1e926f40a0722d106563777ef.png)
A.![]() | B.![]() |
C.![]() | D.![]() |
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解题方法
2 . 设
是两个单位向量,x,y是实数.若
与
的夹角是
,
,则( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/10814bc3db929e79874befe96cf4e3d4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0411792b587ddd3e04440392f011c224.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b95d660852c5226ff65a21cfb36b8b39.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d88591679796c52024d11c4de641bdb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b99d2d50d775c6f5ab9d47f7eaabcc23.png)
A.x的最大值为1 | B.x的最大值为![]() |
C.![]() ![]() | D.![]() ![]() |
您最近一年使用:0次
解题方法
3 . 设非负实数
,
,
满足
,则
的( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d053b14c8588eee2acbbe44fc37a6886.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e81e59019989b7dc2fb59b037ef6e010.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/305a8cc6a2de01535008282cdc2339b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e1433c8103033c67232f2f9ae189608d.png)
A.最小值为![]() | B.最小值为![]() |
C.最大值为![]() | D.最大值为![]() |
您最近一年使用:0次