1-1/80*5x+1/80*4(x+2)

来源：蜘蛛抓取(WebSpider) 时间：2014-11-08 10:59 标签： x的平方减5x加4
①[1-1/(x-1)][x/(x+1)+1]÷[1-3x/(1-x^2)] ②计算:[x^2-4/(x^2-4x+4)-x-2/(x+2)]÷x/(x-2)③2/（a+1)-a-2/(a^2-1)÷a^2-2a/（a^2-2a+1）_百度作业帮
①[1-1/(x-1)][x/(x+1)+1]÷[1-3x/(1-x^2)] ②计算:[x^2-4/(x^2-4x+4)-x-2/(x+2)]÷x/(x-2)③2/（a+1)-a-2/(a^2-1)÷a^2-2a/（a^2-2a+1）
①[1-1/(x-1)][x/(x+1)+1]÷[1-3x/(1-x^2)] =[(x-1-1)/(x-1)][(x+x+1)/(x+1)]÷[(1-x^2-3x)/(1-x^2)]=[(x-2)/(x-1)][(2x+1)/(x+1)]÷[(1-x^2-3x)/(1-x^2)]=[(2x^2+x-4x-2)/(x^2-1)]*[(1-x^2)/(1-x^2-3x)]=[(2x^2-3x-2)/(x^2-1)]*[-(x^2-1)/(1-x^2-3x)]=-(2x^2-3x-2)/(1-x^2-3x)=(2x^2-3x-2)/(x^2+3x-1)②计算:[x^2-4/(x^2-4x+4)-x-2/(x+2)]÷x/(x-2)=[(x+2)(x-2)/(x-2)^2-x-2/(x+2)]÷x/(x-2)=[(x+2)/(x-2)-x-2/(x+2)]÷x/(x-2)=[((x+2)^2-(x-2)^2)/(x-2)(x+2)] *(x-2)/x=[((x+2)+(x-2))((x+2)-(x-2))/(x-2)(x+2)] *(x-2)/x=[2x*4/(x-2)(x+2)] *(x-2)/x=8/(x+2)③2/（a+1)-a-2/(a^2-1)÷a^2-2a/（a^2-2a+1）=2/（a+1)-a-2/(a+1)(a-1)* (a-1)^2/a(a-2)=2/（a+1)-(a-1)/a(a+1)=(2a-(a-1))/a(a+1)=(a+1)/a(a+1)=1/a
1) [1-1/(x-1)][x/(x+1)+1]÷[1-3x/(1-x^2)]
=[(x-2)/(x-1)][(2x+1)/(x+1)]÷[(x^2+3x-1)/(x^2-1)] =[(2x^2-3x-2)/(x^2-1)]÷[(x^2+3x-1)/(x^2-1)] =(2x^2-3x-2)/(x^2+3x-1)求高手高数不等式 （2-√5）/3≤ x2+√5x+1 / 2x2+x+2 ≤（2+√5）/5求证对任意实数X有（2-√5）/3≤ x2+√5x+1 / 2x2+x+2 ≤（2+√5）/5【（x）²+√5x+1】 /【 2（x）²+x+2 】_百度作业帮
求高手高数不等式 （2-√5）/3≤ x2+√5x+1 / 2x2+x+2 ≤（2+√5）/5求证对任意实数X有（2-√5）/3≤ x2+√5x+1 / 2x2+x+2 ≤（2+√5）/5【（x）²+√5x+1】 /【 2（x）²+x+2 】
（2-根号5）/3≤(x^2+根号5x+1)/(2x^2+x+2)≤（2+根号5）/5 分母2x^2+x+2=2(x+1/4)^2+15/8恒＞0,两边同乘以分母,不等式可以转化为：3x^2+3根号5x+3≥(2-根号5）*(2x^2+x+2).（1）5x^2+5根号5x+5≤(2+根号5）*(2x^2+x+2).（2）由（1）得：(2根号5-1)x^2+2(2根号5-1)x+2根号5-1≥0x^2+2x+1≥0(x+1)^2≥0x为任意实数由（2）得：5x^2+5根号5x+5≤(2+根号5）*(2x^2+x+2)(2根号5-1)x^2+2(1-2根号5)x+2根号5-1≥0x^2-2x+1≥0(x-1)^2≥0x为任意实数所以：x为任意实数
中间那个X2什么意思x^2么？ 还有你中间那个分式能加个括号么，分子分母是什么都不清楚啊

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