X分之Y减去Y分之X求3X加X平方Y平方加3Y平分之X平减X平方Y平方加Y平方
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x+3y分之2x-y等于2(2x-y)/(x+3y)=2代数式x+3y分之4x-2y减去2x-y分之4x+12y=2(2x-y)/(x+3y)-4(x+3y)/(2x-y)=2*2-4*(1/2)=4
(2x-y)/(x+3y)=2所以原式=2(2x-y)/(x+3y)-3(x+4y)/(2x-y)=2(2x-y)/(x+3y)-3/[(2x-y)/(x+3y)]=2×2-3/2=5/2
x/y=3x=3y(x^2+y^2-xy)/(x^2-y^2)=(9y^2+y^2-3y^2)/(9y^2-y^2)=7y^2/8y^2=7/8
令a=x/2=y/3=-z/5x=2a,y=3a,z=-5a则原式=(4a+3a-15a)/(2a)=-8a/2a=-4
1/x-1/y=2y-x=2xyx-y=-2xy(3x+7xy-3y)/(2x-3xy-2y)=[3(x-y)+7xy]/[2(x-y)-3xy]=[-6xy+7xy]/[-4xy-3xy]=xy/[
1.33又五分之一2.213.13分之124.a=_-3___时,它有最大值为_3___
x+y=-3x=-y-3xy=2(-y-3)y=2-y²-3y-2=0y²+3y+2=0(y+1)(y+2)=0y1=-1y2=-2一、当y1=-1时,x1=-2,根号y分之x加根
直接设X=1,Y=0.5.带入后式得出10
4(x+y)-3(x-y)=14x+7y=14(x+y)/2+(x-y)/3=6两边同乘以6,得3(x+y)+2(x-y)=365x+y=36则x+7(36-5x)=14x=7,y=1
此题简单做法你直接可以设X=1,Y=0.5,使其满足前面的条件即可,带入后面分式,后面的式子中文表述不清,
令a=x/2=y/3=-z/5x=2a,y=3a,z=-5a则原式=(4a+3a-15a)/(2a)=-8a/2a=-4
根号下大于等于0x²-4>=0,x²>=44-x²>=0,x²
用x分之3加y分之4乘以(x+y),然后化简,再用均值不等式就出来了……(3/x+4/y)乘(x+y)等于7+3y/x+4x/y然后由于x,y大于0,所以用均值不等式即可……
令2分之X=3分之y=4分之z=mX+Y+Z=2m+3m+4m=9mX+Y-Z=2m+3m-4m=m一比等于9
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
2/(x-y)-(x+y)/(x-y)^2=[(2x-2y)-(x+y)]/(x-y)^2=(x-3y)/(x-y)^2
是(x-y)分之(x+y)*(x+y)分之(x-y)如果是,那么:(x-y)分之(x+y)*(x+y)分之(x-y)=1
x/3=y/4=z/5x=3/4y,z=5/4y(x+y-z)/(x-y+z)=(3/4y+y-5/4y)/(3/4y-y+5/4y)=1/2y/y=1/2
原式=[x/(x-y)]*[y^2/(x+y)]-[x^4y/(x^2+y^2)(x^2-y^2)]/[x^2/(x^2+y^2)]=xy^2/(x^2-y^2)-x^2y/(x^2-y^2)=xy(
解1题原式=[(x+y)/x]-[x/(x-y)]+[y²/(x²-xy)]=[(x+y)/x]-[x/(x-y)]+{y²/[x(x-y)]}={(x+y)(x-y)/