x2+y2+$\frac{1}{x^2}+\frac{1}{y^2}$1x2 +1y2 =4
<=> \(x^2-2+\frac{1}{x^2}+y^2-2+\frac{1}{y^2}=0\)
<=>\(\left(x+\frac{1}{x}\right)^2+\left(y+\frac{1}{y}\right)^2=0\)
=> \(x=\frac{1}{x}\) và \(y=\frac{1}{y}\)
=> \(x=1;-1\) và \(y=1;-1\)
tim x,y biet \(\frac{1}{x}+\frac{1}{y}+\frac{1}{z}=0\)
tinh gtbt: \(A=\frac{xy}{z^2}+\frac{yz}{x^2}+\frac{zx}{y^2}\)
tim x,y biet \(\frac{1}{x}+\frac{1}{y}+\frac{1}{z}=0\)
tinh gtbt: \(A=\frac{xy}{z^2}+\frac{yz}{x^2}+\frac{zx}{y^2}\)
tim x,y biet \(\frac{1}{x}+\frac{1}{y}+\frac{1}{z}=0\)
tinh gtbt: \(A=\frac{xy}{z^2}+\frac{yz}{x^2}+\frac{zx}{y^2}\)
tim x,y biet \(\frac{1}{x}+\frac{1}{y}+\frac{1}{z}=0\)
tinh gtbt: \(A=\frac{xy}{z^2}+\frac{yz}{x^2}+\frac{zx}{y^2}\)
tim x,y biet \(\frac{1}{x}+\frac{1}{y}+\frac{1}{z}=0\)
tinh gtbt: \(A=\frac{xy}{z^2}+\frac{yz}{x^2}+\frac{zx}{y^2}\)
cho pt: x^2-2.(m-2)+m^2=2m-3
Tim m de pt co 2 nghiem phan biet x1,x2 thoa man
\(\frac{1}{x1}+\frac{1}{x2}=\frac{x1+x2}{x}\)
cac ban oi giup minh di minh can gap lam
nếu x;y;z là các số dương thì \(^{\frac{x2}{y+z}+\frac{y2}{x+z}+\frac{z2}{x+y}>=\frac{x+y+z}{2}}\)
Tim min, max cua:
\(A=\frac{x^2+y^2}{x^2+2xy+y^2}\)
\(B=\frac{x^2}{x^4+1}\)
\(C=(x^2+\frac{1}{y^2})(y^2+\frac{1}{x^2})\)
1.
a.(-xy)(-2x2y+3xy-7x)
b.(1/6x2y2)(-0,3x2y-0,4xy+1)
c.(x+y)(x2+2xy+y2)
d.(x-y)(x2-2xy+y2)
2.
a.(x-y)(x2+xy+y2)
b.(x+y)(x2-xy+y2)
c.(4x-1)(6y+1)-3x(8y+4/3)