ta có: [tex]VT=(x^2+\frac{1}{4}+y+\frac{1}{2})(y^2+\frac{1}{4}+x+\frac{1}{2})\geq (x+y+\frac{1}{2})^2=x^2+y^2+\frac{1}{4}+2xy+x+y\geq 4xy+x+y+\frac{1}{4}=(2x+\frac{1}{2})(2y+\frac{1}{2})[/tex]
(dấu = xảy ra khi [tex]x=y=\frac{1}{2}[/tex])
mà VP=(2x+1/2)(2y+1/2)
=>x=y=1/2
bạn kt lại nha!
ta có: [tex]VT=(x^2+\frac{1}{4}+y+\frac{1}{2})(y^2+\frac{1}{4}+x+\frac{1}{2})\geq (x+y+\frac{1}{2})^2=x^2+y^2+\frac{1}{4}+2xy+x+y\geq 4xy+x+y+\frac{1}{4}=(2x+\frac{1}{2})(2y+\frac{1}{2})[/tex]
(dấu = xảy ra khi [tex]x=y=\frac{1}{2}[/tex])
mà VP=(2x+1/2)(2y+1/2)
=>x=y=1/2
bạn kt lại nha!