dy dx xy-x^3y^3=0的同届
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(2x+y)/(x^2-2xy+y^2)X(x-y)=(2x+y)/(x-y)²*(x-y)=(2x+y)/(x-y)x-3y=0,x=3y(2x+y)/(x-y)=(6y+y)/(3y-y
75=(2x+3y)(3x+2y) =6x^2+13xy+6y^2 =6(x+y)^2+xy>=24xy+xy=25xyxy<=3x+y>=2vxy=2v3最小值2v3再问:6(x+y)^2+xy
x平方+y平方-4x+6y+13=0(x-2)^2+(y+3)^2=0x=2,y=-3;带入要求的表达式即可.再问:怎么算出x=2y=-3的???再答:例如:a^2+b^2=0就只有a=0,b=0才成
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,
3x=4Y.X/Y=4/3,x-y)/y=(X/Y)-1=1/3,(3x+2y)/(2x+3y)=(4Y+2y)/(8/3y+3y)=18/17(因为3x=4Y,2x=8/3y)再问:若3X-4Y=0
2x-y-3=3x+2y+1=0,x=5/7,y=-11/7
可以得出x.x+y.y-6x-8y+25=x.x-6x+9+y.y-8y+16=(x-3).(x-3)+(y-4).(y-4)=0因为(x-3).(x-3)>=0,(y-4).(y-4)>=0所以x=
X+Y分之X-Y等于3x=-2yX+Y分之2(x-y)减X+Y分之3X+Y=(-x-3y)/(x+y)=1
平面区域的三个顶点为O(0,0),A(0,14/3),B(2,2)(y+1)/(x+2)即是区域内一点P(x,y)与点C(-2,-1)连线的斜率.由数形结合可知1/2≤kPC≤17/6.所以(y+1)
因为(x-y)/(x+y)=3,则(x+y)/(x-y)=1/3则5(x-y)(x+y)-(x+y)/2(x-y)=5*3-1/(3*2)=15-1/6=89/6
c∵x+y≠0∴x≠-y∵3x-6y/x+y=0∴3x-6y=0∴x=2y∴x=2y且x≠-y
3x^2+xy-2y^2=0推出(3x-2y)(x+y)=0推出x=-y或x=(2/3)y{(x+y)/(x-y)+4xy/(y^2-x^2)}/{(x+3y)*(x-y)}/x^2-9y^2推出:{
3x^2y+x^3y'+3y^2y'-2=0=>(x^3+3y^2)y'=2-3x^2y∴y'=(2-3x^2y)/(x^3+3y^2)
3x-5y=0,则x+y/x=(8/5),x-y/y=(2/3),2x-3y/2x+3y=(1/19)因为3x-5y=0所以3x=5y设x=5,y=3,可以解得3x-5y=0,则x+y/x=(8/5)
|3-y|+|x+y|=0,且|3-y|≥0,|x+y|≥0,所以3-y=0,x+y=0,所以y=3,x=-3.所以x+yxy=-3+3-3×3=0-9=0.答:x+yxy的值为0.
线性规则,画出可行性区域,得出x=4/5,y=12/5时,z的最大值为48/25
x=-2.5y=-3再问:过程再答:2x+y/3-2y=0①2(2x+y)-5=7y②展开②式,4x+2y-5=7y,移项整理的得4x-5y=5③将①整理得2x-5y/3=0④将④×2得4x-10y/
y=1/3*3x(16-3x)
绝对值项恒非负,两绝对值项之和=0,两绝对值项分别=03x-y=0(1)x+y=0(2)(1)+(2)4x=0x=0,代入(2)y=-x=0(x-y)/(xy)无意义,因此题目错了.
x²+y²-4x+6y+13=0x²-4x+4+y²+6y+9=0(x-2)²+(y+3)²=0x=2,y=-3代入即可得出答案(3x+y)