y等于x加2分之根号x的平方减4加根号4减x的平方加1,求根号x加y-搜答案-搜搜考试网

根号下大于等于0x²-3>=0,x²>=33-x²>=0,x²

解,x^2+根号2y=根号3；y^2+根号2x=根号3.因为x≠y,且x,y都为正数,所以x^2不等于y^2,即x^2=根号2x,y^2=根号2y,解得x,y一个等于0另一个等于2开三次方根,所以xy

x^2-2x+y^2+6y+10=0x^2-2x+1+y^2+6y+9=0(x-1)^2+(y+3)^2=0x-1=0,y+3=0x=1,y=-3(x-y)/(x+y)=4/(-2)=-2

即x=(√11+√7)/2——是这个吗?y=(√11-√7)/2x+y=√11xy=(√11+√7)(√11-√7)/4=(11-7)/4=1∴原式=(x+y)²-3xy=11-3=8

y=2分之x的平方减7x加3

y=√2+√(x^2-2x+1/3)=√[(x-1)^2-2/3]+√2考虑到定义域要求：x^2-2x+1/3>=0所以x>=1+√6/3或者x

看看能理解吗

等我给你写纸上啊再答：

先采必答

x等于根号2加1,y等于根号2减1所以x+y=√2+1+√2-1=2√2x-y=(√2+1)-(√2-1)=2所以x²-y²=(x+y)(x-y)=2√2×2=4√2

答案是2X是1Y是－1看定义域根号下的部分大于等于零,所以X只能等于1答案就出来了

（x2-y2）/(x-y)2=(x+y)/(x-y)代入x、y得√3/6

x²+y²-4x-2y+5=0x²-4x+4+y²-2y+1=0(x-2)²+(y-1)²=0x-2=0x=2y-1=0y=1√(x+y)/

根号下大于等于0x²-4>=0,x²>=44-x²>=0,x²

如果问题写清楚一些就好啦

x＝﹙√3＋√2﹚/﹙√3－√2﹚＝5＋2√6y＝﹙√3－√2﹚/﹙√3＋√2﹚＝5－2√6x·y＝﹙5＋2√6﹚﹙5－2√6﹙﹚＝1x＋y＝5＋2√6＋5－2√6＝10y/x＋x/y＝﹙x²

3∵x/y=1/2∴y=2x故（x^2+2xy+y^2)/(x^2-xy+y^2)=(x+y)^2/(x^2-xy+y^2)=(x+2x)^2/(x^2-x·2x+4x^2)=9x^2/(3x^2)=

y=√(2x-1)/(x²+x-2)=√(2x-1)/(x+2)(x-1)√(2x-1)>=0x>=1/2(x+2)(x-1)≠0x≠-2且x≠1综上x>=1/2且x≠1

证明:∵[√(x²+1)-1]²≥0.即x²+1-2√(x²+1)+1≥0.∴x²+2≥2√(x²+1).不等式两边同除以√(x²