从3,0,﹣1,﹣2,﹣3这五个数中,随机抽取一个数,作为函数y=(5

30,﹣1,﹣2,﹣3这五个数中,随机抽取一个数,作为函数y=5m2x和关于x的方程(m+1x2+mx+1=0m的值,恰好使所得函数的图象经过第一、三象限,且方程有实数根的概率为  

答案

【解答】解:所得函数的图象经过第一、三象限,

5m20

m25

30,﹣1,﹣2,﹣3中,3和﹣3均不符合题意,

m=0代入(m+1x2+mx+1=0中得,x2+1=0=40,无实数根;

m=1代入(m+1x2+mx+1=0中得,﹣x+1=0x=1,有实数根;

m=2代入(m+1x2+mx+1=0中得,x2+2x1=0=4+4=80,有实数根.

故方程有实数根的概率为

 

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