已知|x 2| (y-2分之1)
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y=(x2-ax+b)/(x2+x+1),分母=(x+1/2)2+3/4≥3/4Y(x2+x+1)=(x2-ax+b),(y-1)x2+(y+a)x+(y-b)=0,此方程有实数根所以⊿≥0,即(y+
x-y=1,(x-y)^2=x^2+y^2-2xy=12xy=25-1=24,xy=12(x+y)^2=x^2+y^2+2xy=25+24=49x^2-xy+y^2=25-12=13
(x-1)^2+(y-1)^2=1令x-1=sinay-1=cosa则x=1+sina,y=1+cosax^2+y^2=1+2sina+(sina)^2+1+2cosa+(cosa)^2=3+2(si
解:原式=(x-y)×(xy)分之(xy)的平方-(x-y)的平方乘以(x的平方×y的平方)分之(y的平方-x的平方)=-(xy分之4)当x=2根号3,y=2-根号3时;代入-(xy分之4),结果为5
x^2-3x+2=0(x-2)(x-1)=0x=2或x=1当x=2时x^2+1/x^2=2^2+1/2^2=4+1/4=17/4当x=1时x^2+1/x^2=1^2+1/1^2=1+1=2
设2分之x=3分之y=4分之z=k∴x=2k,y=3k,z=4kx2+y2+z2分之xy+yz+zx=(6k²+12k²+8k²)/(4k²+9k²+
关系写清楚点,没看明白再问:y等于x平方-2小于等于xx小于等于aa大于等于-2
(x²+2x+1)/(x²-y²)÷(x+1)/(x-y)=(x+1)²/(x+y)(x-y)×(x-y)/(x+1)=(x+1)/(x+y)【俊狼猎英】团队为
已知:(x²+1)/x=x²/x+1/x=x+1/x所以:x²+1/x²=x²+1/x²+2-2=(x+1/x)²-2
X2+Y2+8X+6Y+25=0x²+8x+16+y²+6y+9=0(x+4)²+(y+3)²=0∴x+4=0y+3=0x=-4y=-3X2+4XY+4Y2分之
[(x^2+y^2)-(x-y)^2+2y(x-y)]÷4y=1(x^2+y^2-x^2+2xy-y^2+2xy-2y^2)÷4y=1(4xy-2y^2)4y=12x-y=24x/(4x^2-y^2)
解题思路:完全平方公式解题过程:varSWOC={};SWOC.tip=false;try{SWOCX2.OpenFile("http://dayi.prcedu.com/include/readq.
假设该不等式的两根为y1,y2则不等式的解集为[y1,y2]即y∈[y1,y2]题目已知:y∈[1,2]所以,y1=1,y2=2还请及时采纳,谢谢~~
解题思路:关键是理解所求的几何意义即可的了,,,,。解题过程:
带入x=3y,分母为9y^2-6y^2+y^2=4y^2.分子为7y*2y=14y^2.所以原式=7/2.
原式=(4x2-y2+x2+2xy+y2-4x2+2xy)÷(-4x)=(x2+4xy)÷(-4x)=-14x-y,∵2y+x2=10,∴y=5-x4,则原式=-14x-5+14x=-5.
根号下则x²-4>=04-x²>=0同时成立则x²=4x=±2分子x+2=4或0所以y=4/(0+0-1)=-4或0所以3x+4y=6-4*4=-10或3*(-2)+0=
原式=x2-2x2+4y+2x2-2y=x2+2y,当x=-1,y=12时,原式=(-1)2+2×12=2.
可设x²+y²=t.则t(t-1)=2.===>t²-t-2=0.===>(t-2)(t+1)=0.===>t=2.即x²+y²=2.
x1+x2=4x1x2=-1(x1+x2)^2/(1/x1+1/x2)=(x1+x2)^2*x1x2/(x1+x2)=x1x2*(x1+x2)=-4