已知:x1,x2是方程x²+6x+3=0的两实数根,则x2/x1-x1/x2的值为
人气:156 ℃ 时间:2019-10-19 16:15:44
解答
x1,x2是方程x²+6x+3=0的两实数根,
则由根与系数的关系(即韦达定理):x1+x2=-6,x1*x2=3;
而x2/x1-x1/x2=(x2^2-x1^2)/x1*x2
=(x1-x2)(x1+x2)/x1*x2
把x1+x2=-6,x1*x2=3代入上式,得:x2/x1-x1/x2=(x1-x2)(x1+x2)/x1*x2=-2(x1-x2)
而(x1-x2)^2=(x1+x2)^2-4x1*x2=24,所以:x1-x2=±2√6;
则x2/x1-x1/x2=-2(x1-x2)=±4√6;
即x2/x1-x1/x2的值为±4√6;
如果不懂,请Hi我,
推荐
猜你喜欢
- 一辆汽车从甲地到乙地,行了全程的40%,离终点还有5千米,甲乙两地相距多少千米
- the big minute hand did not move.为什么不是the big minute hand was not move.
- However mean your life is,meet it and live it ;do not shun it and call it hard names.It is not so bad as you are.It look
- 已知直线l1:y=x+m和L2:y=-2x+n交于点P(-2,0),l1交y轴于点A,l2交y轴于点B.
- 『汉译英』“第二,我们应该把老师当成朋友.不要害怕老师,多与老师相处.”求翻译
- 士不可不弘毅,任重而道远.
- 民族资本主义与官僚资本主义的区别
- "我来了,我看见了,我征服了"的英文原文是什么?