là \(4x+\dfrac{1}{x^2}+2x+2\) hay là \(\dfrac{4x+1}{x^2+2x+2}\) cái neog:0
\(P=\dfrac{4x+1}{x^2+2x+2}=\dfrac{x^2+2x+2-x^2+2x-1}{x^2+2x+2}=1-\dfrac{\left(x-1\right)^2}{x^2+2x+2}\le1\)
"=" xảy ra <=> x - 1 = 0 <=> x = 1
Vậy Max P = 1 <=> x = 1
P = \(\dfrac{4x+1}{x^2+2x+2}=\dfrac{-4x^2-8x-8+4x^2+12x+9}{x^2+2x+2}=-4+\dfrac{\left(2x+3\right)^2}{x^2+2x+2}\)
\(\ge-4\)
"=" xảy ra <=> 2x + 3 = 0 <=> x = -1,5
Vậy Min P = -4 <=> x = -1,5