Question

tìm GTLN

A=\(\dfrac{2010}{x^2-2x+1001}\)

B=\(\dfrac{1000}{x^2+y^2-20\left(x+y\right)+2210}\)

C=\(\dfrac{100}{25x^2-20x+14}\)

Làm ơn!!!

Answer 1

\(a=\dfrac{2010}{x^2-2x+1001}=\dfrac{2010}{x^2-2x+1+1000}=\dfrac{2010}{\left(x-1\right)^2+1000}\le\dfrac{101}{100}\)

\(b=\dfrac{1000}{x^2+y^2-20\left(x+y\right)+2210}=\dfrac{1000}{x^2+y^2-20x-20y+2210}=\dfrac{1000}{x^2+y^2-20x-20y+100+100+2010}=\dfrac{1000}{\left(x-10\right)^2+\left(y-10\right)^2+2010}\le\dfrac{100}{201}\)

\(c=\dfrac{100}{25x^2-20x+14}=\dfrac{100}{25x^2-20x+4+10}=\dfrac{10}{\left(5x-2\right)^2+10}\le1\)