7956 nha bạn

tích nha

ababab = ab x 10101

= ab x 3 x 7 x 13 x 37

Mà ab chia hết cho 3 x 7 x 13 x 37

Mà ab có 2 chữ số

Nên ab không thể đồn thời chia hết cho 3 x 7 x 13 x 37

Vậy ababab không phải số chính phương

THỂ TÍCH LÀ 1728 CM³

\(B=\dfrac{2\sqrt{x}+15}{\sqrt{x}+2}=\dfrac{2\left(\sqrt{x}+2\right)+11}{\sqrt{x}+2}=2+\dfrac{11}{\sqrt{x}+2}\text{≤}2+\dfrac{11}{2}=\dfrac{15}{2}\) ⇒ \(B_{Max}=\dfrac{15}{2}."="\text{⇔}x=0\)

\(A=3x+2\sqrt{x}+5\text{ ≥}5\left(x\text{ ≥}0\right)\)

⇒ \(A_{MIN}=5."="\) ⇔ \(x=0\)

P/s : Làm bừa :))

\(A=\sqrt[3]{20+14\sqrt{2}}+\sqrt[3]{20-14\sqrt{2}}=\sqrt[3]{2\sqrt{2}+3.2.2+3.\sqrt{2}.4+8}+\sqrt[3]{8-3.\sqrt{2}.4+3.2.2-2\sqrt{2}}=\sqrt[3]{\left(\sqrt{2}+2\right)^3}+\sqrt[3]{\left(2-\sqrt{2}\right)^3}=\sqrt{2}+2+2-\sqrt{2}=4=\sqrt{16}\) \(B=2\sqrt{5}=\sqrt{20}\)

⇒ \(A< B\)

 < hơn ak
 

\(a.A=\left(\dfrac{x-5\sqrt{x}}{x-25}-1\right):\left(\dfrac{25-x}{x+2\sqrt{x}-15}-\dfrac{\sqrt{x}+3}{\sqrt{x}+5}+\dfrac{\sqrt{x}-5}{\sqrt{x}-3}\right)=\dfrac{-5}{\sqrt{x}+5}:\dfrac{25-x-x+9+x-25}{\left(\sqrt{x}+5\right)\left(\sqrt{x}-3\right)}=\dfrac{-5}{\sqrt{x}+5}.\dfrac{\left(\sqrt{x}+5\right)\left(\sqrt{x}-3\right)}{-\left(\sqrt{x}-3\right)\left(\sqrt{x}+3\right)}=\dfrac{5}{\sqrt{x}+3}\) ( x ≥0 ; x # 9 ; x # 25 )

\(b.A< 1\) ⇔ \(\dfrac{5}{\sqrt{x}+3}< 1\)

⇔ \(\dfrac{2-\sqrt{x}}{\sqrt{x}+3}< 0\)

⇔ \(2-\sqrt{x}< 0\)

⇔ \(x>4\) ( x # 9 ; x # 25 )

KL.................

\(\frac{1}{4}<\frac{1}{a}<\frac{2}{3}\Rightarrow\int^{\frac{1}{4}<\frac{1}{a}}_{\frac{1}{a}<\frac{2}{3}}\)

\(\Rightarrow\int^{4>a}_{\frac{3}{3a}<\frac{2a}{3a}}\)

1 ; -1 ; 1003 ; -1003 có lẽ vậy

co tat ca 105 so