\(A=\frac{x}{\left(x+2019\right)^2}\)
Với \(x\le0\Rightarrow A\le0\)
Với \(x>0\Rightarrow A=\frac{x}{x^2+4038x+2019^2}=\frac{1}{x+\frac{2019^2}{x}+4038}\)
\(\Rightarrow A\le\frac{1}{2\sqrt{x.\frac{2019^2}{x}}+4038}=\frac{1}{8076}\)
\(\Rightarrow A_{max}=\frac{1}{8076}\) khi \(x=2019\)
Tim GTLN cua:
A= 2/ (x+√ x+1)
tim GTNN cua Q=2018√x+2018 +√2019-x
cho x, y, z ko am 1/(1+2x)+1/(1+2y)+1/(1+2z)=2. tim GTLN cua P=xyz
Tìm GTLN của \(A=\sqrt{x-2}+2\sqrt{x+1}+2019-x\)
Tìm GTLN:
\(\frac{\sqrt{x-2019}}{x+2}+\frac{\sqrt{x-2020}}{x}\)
P =\(\dfrac{\sqrt{y-2}}{y}\)
tim GTLN cua P
Tim GTLN: \(\sqrt{\frac{\sqrt{x}-1}{\sqrt{x}+2}}\)
tim GTNN cua P=\(\sqrt{x^2+x+1}+\sqrt{x^2-x+1}\)
Cho bieu thuc A=\(\left(\dfrac{4}{x-\sqrt{x}}+\dfrac{\sqrt{x}}{\sqrt{x}-1}\right)\div\dfrac{1}{\sqrt{x}-1}\)
a/ Tim dieu kien cua x de bieu thuc A co gia tri xac dinh
b/ Rut gon A
c/ Tinh gia tri cua A khi x = \(4-2\sqrt{3}\)
d/ Tim gia tri nho nhat cua A
