圆 (x-1)² (y-1)²=1点到直线x 2y 2=0的最短距离
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解题思路:用x2的取值范围、二次函数的的性质、均值不等式,换元法求函数的值域解题过程:
由2(X+Y)3X+3Y=24得:2(X+Y)X+Y=8①;(X+Y/2X)XY/2Y=1得:X+Y=4②;由①、②得出Y=8(1-X),进入②知X=4/7;即Y=24/7
3(x+y)+3(y-x)=1(1)3(x+y)+4(y-x)=-1(2)(2)-(1)得y-x=-2(3)代入(1)3(x+y)-6=1x+y=7/3=>x=7/3-y又由(3)得x=y+2y+2=
Dx^y+x^-y=2根号2===>(x^y+x^-y)^2=8===>x^2y+x^-2y+2=8===>x^2y+x^-2y=6(x^y-x^-y)^2=x^2y+x^-2y-2=6-2=4==>
x=4,y=0.5,x+y=4.5(与人家的做法一样……)(1)解题思路是以S3为基准,用S3表示出S1,S2,S4即可.在三角形BCD中有:S2/S3=DF/CF,故S2=(DF/CF)S3;同理,
解题思路:【1】把圆C的方程化为标准形式,确定圆心坐标及半径。【2】应用弦长公式求出AB.解题过程:
这样算,分离变量:x²+x=(x+1)²-(x+1)然后,除下来,就等于x+1-1=x注意,x≠-1!
因为X-Y=1所以原式=x*1+y*(-1)+2013=x-y+2013=1+2013=2014
1)x(x-y)(x+y)-x(x+y)^2=x((x-y)(x+y)-(x+y)^2)=x(x^2-y^2-x^2-2xy-y^2)=x(-2xy-2y^2)=-2xy(x+y)2)(2a+b)(2
令m=x(x+y),n=y(x+y)则m-n=x^2-y^2,于是m-n+1=2x^2,1-m+n=2y^2(m+n-1)^2=4x^2y^2=(m-n+1)(1-m+n)整理得:m^2+n^2-m-
1.1/x+1/y=(x+y)/xy=-1/(x+y)去分母可得,(x+y)^2+xy=0即x^2+y^2=-3xy所以y/x+x/y=(x^2+y^2)/xy=-32.由1/x-1/y=5可得y-x
解题思路::∵x+y=0,x+13y=1,解得x=1/12,y=-1/12∴x²+12xy+13y²=1/144-1/12+13/144=14/144-1/12=2/144=1/72解题过程:已知x+
解(x-y)(x+y)-(x-2y)²+x(3x-5y)-(x-y)(x-2y)=(x²-y²)-(x²-4xy+4y²)+(3x²-5xy
3(x+y)-4(x-y)=4(x+y)/2+(x-y)/6=1令a=x+y,b=x-y3a-4b=4(1)a/2+b/6=1则3a+b=6(2)(2)-(1)5b=2b=2/5a=(6-b)/3=2
4x=9yx=9/4*y(1)(x+y)/y=[(9/4)y+y]/y=(9/4+1)y/y=9/4+1=13/4(2)(y-x)/2x=[y-(9/4)y]/[2*(9/4)y]=(1-9/4)y/
取整
哥!你那个是x方y方吧!有这么个公式x方-y方=(x+y)(x-y)所以得到了(x+y)(x-y)-(x+y)这时候提取公因式(x+y)就得到了(x+y)(x-y-1)再问:是啊,怎么提(X+Y)他那
完整设1/(x+y)=a,1/(x-y)=b原方程组可变为4a+6b=39b-a=1a=9b-136b-4+6b=3b=1/6,a=1/2x+y=2x-y=6所以原方程组的解为:x=4,y=-2
(x+y^2+3)dy=(x-y+1)dx或:xdy+ydx+(y^2+3)dy-(x+1)dx=d(xy)+(y^2+3)dy-(x+1)dx=0通解为:xy+y^3/3+3y-x^2/2-x=C