已知y是由方程x^2-x*y y^2=1决定的隐函数,求y对x的导数-搜答案-搜狗做题网

两边对【x】求导,注意,y是x的函数,利用复合函数求导1/[1+(y/x)^2]×(y/x)'=1/2×1/(x^2+y^2)×(x^2+y^2)',也就是：x^2/(x^2+y^2)×(xy'-y)

(x-y)(x+y)(xx-yy)=?

(x-y)(x+y)(xx-yy)=(x^2-y^2)(x^2-y^2)=x^4-2x^2y^2+y^4

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

(x²+xy-12)²+(xy-2y²-1)²=0由于平方数都大于或等于0,所以上式成立的前提是：(x²+xy-12)²=0,即：x&sup

3.c4.A

x^2+y^2-2x+y+k=0x^2-2x+1-1+y^2+y+1/4-1/4+k=0(x-1)^2+(y+1/2)^2-5/4+k=0(x-1)^2+(y-1/2)^2=5/4-k5/4-k>0k

dy^2/dx=dy^2/dy*(dy/dx)//链式法则=2yy'所以x^2+y^2=1两边求导是2x+2yy'=0再问：dy^2/dx=dy^2/dy*(dy/dx)这两个会相等吗?不是很懂为什么

2^(xy)=x+y,当x=0时,y=1(xy)ln2=ln(x+y)两边微分得：(ydx+xdy)ln2=(dx+dy)(x+y)代入x=0,y=1得ln2dx=dx+dy所以,dy=(ln2-1)

XX-YY/(X-Y)(X-Y)约分

XX-YY/(X-Y)(X-Y)=(x^2-y^2)/(x-y)(x-y)=(x+y)(x-y)/(x-y)(x-y)=(x+y)/(x-y)

2/9再问：过程，谢谢再答：由题目得y/x=2/3xy/xx+yy-yy/xx-yy=y/x-(y/x)²=2/3-4/9=2/9

原式=[(x²+y²-2y²)/y]/[(x-y)/xy]×1/(x²-y²)=[(x²-y²)/y]×[xy/(x-y)]×1/

xx+yy+4x-6y+13=0整理得：(x+2)^2+(y-3)^2=0那么只有(x+2)=0(y-3)=0x=-2y=3(x^2-2x)/(x^2+3y^2)=(4+4)/(4+3*9)=8/31

x^2+x-x^2-y=3x-y=3(x-y)^2=9x^2+y^2-2xy=9(x^2+y^2)/2-xy=9/2

方程y=sin(x+y)两边对x求导数有：y'=cos(x+y)(x+y)'=cos(x+y)(1+y')移项整理得：[1-cos(x+y)]y'=cos(x+y)因此：y'=cos(x+y)/[1-

【e^(--x^2)y^2】'=e^(--x^2)*【2yy'--2xy^2】=2e^(--x^2)(x^3--x)=--【e^(--x^2)*x^2】‘,因此e^(--x^2)y^2=C--e^(-

x^2-2x+y^2+6y+10=0(x-1)^2+(y+3)^2=0所以x=1,y=-3x+y=-2x^2表示x的平方

XX+YY+4X-6Y+13=0(X+2)²+(Y-3)²=0X+2=0Y-3=0X=-2Y=3X的Y次方=-8

xx-yy-x-y 因式分解

xx-yy-x-y=(x^2-y^2)-(x+y)=(x+y)(x-y)-(x+y)=(x+y)(x-y-1)

x y x+yy x+y xx+y x y

把所有列都加至第一列,第一列都是2x+2y将2x+2y提出,第一列剩下都是1,此时式外边有一因子（2x+2y）用2,3行加第1行负一倍得1yx+y0xy0x-y-x第一列展开得1*（-x^2-y(x-