\(A=\frac{x^2-3}{\left(x-2\right)^2}=\frac{-3x^2+12x-12+4x^2-12x+9}{\left(x-2\right)^2}\)
\(=-3+\frac{4x^2-12x+9}{\left(x-2\right)^2}=-3+\frac{\left(2x-3\right)^2}{\left(x-2\right)^2}\ge-3\)
Vậy GTNN là - 3 đạt được khi x = 1,5
Cho x+y=z=3;\(A=x^2+y^2+z^2;B=xy+yz+xz\) a) C/M:\(A\ge B\) b) tim GTNN cua A c)tim GTLN cua B d) timf GTNN cua A+B
tim gtnn cua A=x^2+y^2+2xy+2x+2y+3
tim gtnn cua A=7 / 10x -x^2 + 3
cho A= x^2+y^2+z^2+xy+yz+zx .Tim GTNN cua A ,biet x+y+z=3
tim GTNN cua bt sau
A=(x-1)(x+2)(x+3)(x+6)
tim gtnn cua x(x+1)(x+2)(x+3)
tim GTNN cua cac don thuc a)x^2 - 4xy + 5y^2 - 2y + 3
b)x^2 - 2xy + 2y^2 - x +y
tim GTNN cua: 3*x^2+y^2-2*x*y-7
cho x>0,y>0, x+y=2012.
a, tim GTLN cua A= (2x^2+8xy+2y^2)/ (x^2+2xy+y^2)
b, tim GTNN cua B=(1+(2012/x))^2+(1+(2012/y))^2
