\(\sqrt{\dfrac{3}{80}}=\dfrac{\sqrt{15}}{20}\)
\(\sqrt{\dfrac{3}{80}}=\dfrac{\sqrt{15}}{20}\)
9) \(\sqrt{20}\) + 2\(\sqrt{45}\) + \(\sqrt{125}\) - 3\(\sqrt{80}\)
10) \(\sqrt{75}\) - \(\sqrt{5\dfrac{1}{3}}\) + \(\dfrac{9}{2}\) \(\sqrt{2\dfrac{2}{3}}\) + 2\(\sqrt{27}\)
1) Chứng minh rằng : \(\dfrac{1}{\sqrt{1}+\sqrt{2}}\) +\(\dfrac{1}{\sqrt{3}+\sqrt{4}}\)+....+\(\dfrac{1}{\sqrt{79}+\sqrt{80}}\) >4
tính:
\(2\sqrt{5}\)+\(\dfrac{3}{4}\sqrt{80}\)-0,3\(\sqrt{500}\)-\(\dfrac{1}{5}\sqrt{125}\)
rút gọn
a)\(\sqrt{20}\)+\(\sqrt{80}\)-\(\sqrt{45}\)
b)4.\(\sqrt{\dfrac{2}{9}}\)+\(\sqrt{2}\)+\(\sqrt{\dfrac{1}{18}}\)
c)\(\dfrac{1}{\sqrt{3}-1}\)-\(\dfrac{1}{\sqrt{3}+1}\)
d)\(\dfrac{1}{\sqrt{x}-1}\)-\(\dfrac{1}{\sqrt{x}+1}\)+1
e)\(\sqrt{x}\)-2+\(\dfrac{10-x}{\sqrt{x}+2}\)
g)\(\dfrac{1}{\sqrt{x}+2}\)-\(\dfrac{2}{\sqrt{x}-2}\)-\(\dfrac{\sqrt{x}}{4-x}\)
Bài 1: Tính
a) \(\sqrt{1,44.1,21-1,44.0,4}\)
b) \(\dfrac{\sqrt{5}-2}{\sqrt{5}+2}+\sqrt{80}\)
c) \(\sqrt[3]{16}+\sqrt[3]{2}\left(\sqrt[3]{4}-\sqrt[3]{2}\right)\)
Bài 2: C/m
\(\dfrac{1}{\sqrt{a}-\sqrt{b}}:\dfrac{a\sqrt{b}+b\sqrt{a}}{\sqrt{ab}}=\dfrac{1}{a-b}\) với a,b>0, a khác 0
Thực hiện phép tính (rút gọn biểu thức)
a)\(\sqrt{20}\)-3\(\sqrt{45}\)-\(\dfrac{1}{2}\sqrt{80}\)
b) 12\(\sqrt{54}\)-\(\dfrac{2}{5}\)\(\sqrt{150}\)+3\(\sqrt{24}\)
rút gọn biểu thức : \(\dfrac{5-2\sqrt{5}}{\sqrt{5}}\) - ( \(5\sqrt{5}-3\) ) + \(\sqrt{80}\)
Câu 80**: Tam giác ABC có Â = 1200 , AB = AC, BC = 12 . Độ dài đường cao AH là:
A. \(\sqrt{3}\); B . \(\dfrac{\sqrt{3}+1}{2}\) ; C . \(\dfrac{2+\sqrt{3}}{2}\); D.\(2\sqrt{3}\) .
A=\(2\sqrt{20}-\dfrac{2}{\sqrt{3}+1}-\sqrt{80}+\sqrt{4+2\sqrt{3}}\)
B=\(\left(1+\dfrac{x+\sqrt{x}}{1+\sqrt{x}}\right)\left(1+\dfrac{x-\sqrt{x}}{1-\sqrt{x}}\right)\) (0 nhỏ hơn hoặc bằng x; x khác 1)
a) Rút gọn A, B
b) Tìm giá trị của x đề A=4\(\sqrt{B}\)
Help meeeeeeeeeeee