Question

tìm gtln của : A = \(\sqrt{x}-x\)

Answer 1

\(A=-\left(x-\sqrt{x}+\dfrac{1}{4}-\dfrac{1}{4}\right)=-\left(\sqrt{x}-\dfrac{1}{2}\right)^2+\dfrac{1}{4}< =\dfrac{1}{4}\)

Dấu '=' xảy ra khi x=1/4

Answer 2

A = - ( x - √x + 1/4 - 1/4 ) 

A = - ( √x - 1/2)² + 1/4 < = 1/4

dấu ^'=^' xảy ra khi x = 1/4