Cho x, y, z khác 0 thỏa mãn:
x3+y3+z3=1
x(\(\dfrac{1}{z}+\dfrac{1}{y}\))+y(\(\dfrac{1}{x}+\dfrac{1}{z}\))+z(\(\dfrac{1}{x}+\dfrac{1}{y}\))=-2
Tìm giá trị của: S=\(\dfrac{1}{x}+\dfrac{1}{y}+\dfrac{1}{z}\)
1/Tìm x
\(\dfrac{3}{x-3}-\dfrac{6x}{9-x^2}+\dfrac{x}{x+3}=0\)
2/ Cho \(\dfrac{x}{y+z}+\dfrac{y}{z+x}+\dfrac{z}{x+y}=1\)
Tính S = \(\dfrac{x^2}{y+z}+\dfrac{y^2}{z+x}+\dfrac{z^2}{x+y}\)
a) \(\dfrac{1}{\left(x-y\right)\left(y-z\right)}+\dfrac{1}{\left(y-z\right)\left(z-x\right)}+\dfrac{1}{\left(z-x\right)\left(x-y\right)}\)
b) \(\dfrac{1}{x\left(x-y\right)\left(x-z\right)}+\dfrac{1}{y\left(y-z\right)\left(y-x\right)}+\dfrac{1}{z\left(z-x\right)\left(z-y\right)}\)
c) \(\dfrac{x^2}{\left(x-y\right)\left(x-z\right)}+\dfrac{y^2}{\left(y-x\right)\left(y-z\right)}+\dfrac{z^2}{\left(z-x\right)\left(z-y\right)}\)
Cho \(P=\dfrac{x}{y+z}+\dfrac{y}{z+x}+\dfrac{z}{x+y}\)
và \(Q=\dfrac{x^2}{y+z}+\dfrac{y^2}{z+x}+\dfrac{z^2}{x+y}\)
Chứng minh nếu P=1 thì Q=0
Cho x, y , z ≠ 0 thỏa mãn thỏa mãn x + y + z = xyz và \(\dfrac{1}{x}+\dfrac{1}{y}+\dfrac{1}{z}=\sqrt{3}\)
Tính P = \(\dfrac{1}{x^{2^{ }}}+\dfrac{1}{y^2}+\dfrac{1}{z^2}\)
Tính \(A=\dfrac{x+y}{z}+\dfrac{x+z}{y}+\dfrac{y+z}{x}\) biết\(\dfrac{1}{x}+\dfrac{1}{y}+\dfrac{1}{z}=0\)
\(\dfrac{1}{(x-y)(y-z)}+\dfrac{1}{(y-z)(z-x)}+\dfrac{1}{(z-x)(x-y)}\)
cho x,y, z khác 0 thỏa mãn \(\dfrac{1}{xy}+\dfrac{1}{yz}+\dfrac{1}{xz}=0.\)tính \(\dfrac{x^2}{yz}+\dfrac{z^2}{xy}+\dfrac{y^2}{xz}\)
Cho x, y , z \(\ne\) 0 thỏa mãn thỏa mãn x + y + z = xyz và \(\dfrac{1}{x}\) + \(\dfrac{1}{y}\) + \(\dfrac{1}{z}\) = \(\sqrt{3}\) . Tính giá trị biểu thức P = \(\dfrac{1}{\sqrt{x^2}}\) + \(\dfrac{1}{\sqrt{y^2}}\) + \(\dfrac{1}{\sqrt{z^2}}\)