xyx减zz等于yy
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YYDistrictXXCityofnewbuildingmaterialsZZplant
10YB
令x/3=y/4=z/5=k;则x=3k,y=4k,z=5k;(xy+yz+xz)/(xx+yy+zz)=(3k*4k+4k*5k+3k*5k)/(3k*3k+4k*4k+5k*5k)=(12+20+
X:Y:Z=1:2:3因为:14(XX+YY+ZZ)=(X+2Y+3Z)^214(XX+YY+ZZ)-(X+2Y+3Z)^2=013X^2+10Y^2+5Z^2-4XY-6XZ-12YZ=0(4X^2
1Y币=一元
由xx+yy+zz=xy+yz+xz得xx+yy+zz-xy-yz-xz=0(x-y)^2+(y-z)^2+(z-x)^2=0故得(x-y)^2=0(y-z)^2=0(z-x)^2=0x=y==z于是
x-z=(x-y)+(y-z)=5+4=9(x-y)²=x²-2xy+y²=25(y-z)²=y²-2yz+z²=16(x-z)²
(X+Y+Z)*(X+Y+Z)=XX+YY+ZZ+2(XY+YZ+XZ)=1,又XY+YZ+XZ=0,所以XX+YY+ZZ=1
官方的话1元人民币一个,要是你在淘宝或者拍拍上买,会便宜一点,但差值不都大,也就几毛钱
X=3K,Y=K,Z=2K(2X方-2Y方+5Z方)/(XY+YZ+ZX)=(2*9-2+5*4)/(3+2+6)=36/11
RoomZZ,UnitYY,BuldingXX,HongshangceRd.,WuchangDist.,Wuhan,Hubeiprovince,P.R.China
xxRoom,XXth(如sixthFloor)Floor,YYUnit,ElectricFactoryWorkshop,TangshanCity,HebeiProvince.和中文是反着起的,从小到
1QB
xx'+yy'+zz'可以由前面的推导过来.|a|=√(x^2+y^2+z^2)|b|=√(x'^2+y'^2+z'^2)|c|=√((x-x')^2+(y-y')^2+(z-z')^2)cosθ=|
1比1咯
x2+y2-z2+2xy/x2-y2+z2-2xz=(x+y)2-z2/(x-z)2-y2=(x+y-z)(x+y+z)/(x-y-z)(x-z+y)=(x+y+z)/(x-y-z)然后就是代入了
用一个变量来表示另外两个变量即可得解.如用Y表示X有X=3Y/4用Y表示Z有z=5Y/4所以(xy+yz+xz)/xx+yy+zz=(3YY/4+5YY/4+15YY/16)/(9YY/16+YY+2
解题思路:由于矩形ABCD的面积等于2个△ABC的面积,而△ABC的面积又等于矩形AEFC的一半,所以可得两个矩形的面积关系解题过程:见解答
如果是xy+xz+yz的话:xy+xz+yz=[(x+y+z)^2-(x*x+y*y+z*z)]/2=5*5-6=19
X=-1,Y=1,Z=-1x=4,y=7,z=10