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?](/uploads/image/z/1972012-4-2.jpg?t=%E5%9C%A8%E5%8C%BA%E9%97%B4%5B-1%2C1%5D%E4%B8%8A%E4%BB%BB%E5%8F%96%E4%B8%A4%E5%AE%9E%E6%95%B0a%2Cb%2C%E5%88%99%E4%B8%80%E5%85%83%E4%BA%8C%E6%AC%A1%E6%96%B9%E7%A8%8Bx2%2B2ax%2Bb2%3D0%E7%9A%84%E4%B8%A4%E6%A0%B9%E9%83%BD%E4%B8%BA%E5%AE%9E%E6%95%B0%E7%9A%84%E6%A6%82%E7%8E%87%E4%B8%BA%E5%A4%9A%E5%B0%91%3F)
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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