在区间[-1,1]上任取两实数a,b,则一元二次方程x2+2ax+b2=0的两根都为实数的概率为多少?
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在区间[-1,1]上任取两实数a,b,则一元二次方程x2+2ax+b2=0的两根都为实数的概率为多少?
在区间[-1,1]上任取两实数a,b,则一元二次方程x2+2ax+b2=0的两根都为实数的概率为多少?
在区间[-1,1]上任取两实数a,b,则一元二次方程x2+2ax+b2=0的两根都为实数的概率为多少?
4a²-(2b)²>0
|a|>|b|
a为横轴,b为纵轴
就是画十字交叉线,然后落在左右两边区间的概率
十字交叉平分正方形
所以自然是1/2
两根都为实数的概率=1/2
不好意思题目看错了,我以为是2b,原来是b平方,哈哈,那简单多了,不用积分了。。。
me to her home. Carey is actually not a student, but a manager. She stays in Li's apartment for free, __2___ has to teach Li oral English for 1 hour every day. “She could hardly speak Chinese at t...
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me to her home. Carey is actually not a student, but a manager. She stays in Li's apartment for free, __2___ has to teach Li oral English for 1 hour every day. “She could hardly speak Chinese at the beginning, and __3___ had to guess what each other meant through gestures, ”said Li.
Two months later, they could talk to each oth
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