b1. Rút gọn
a)\(\frac{5\sqrt{6}+6\sqrt{5}}{\sqrt{5}+\sqrt{6}}\)
b) \(\frac{2\sqrt{7}-4\sqrt{3}}{3\sqrt{35}-6\sqrt{15}}\)
c) \(\frac{12\sqrt{10}-16\sqrt{14}}{6\sqrt{5}-8\sqrt{7}}\)
d) \(\frac{6\sqrt{6}-27}{2\sqrt{2}-3\sqrt{3}}\)
e) \(\frac{-4\sqrt{2}+3\sqrt{5}}{-2\sqrt{10}}\)
1)Tính:
a)(\(\sqrt{3-\sqrt{5}}+\sqrt{3+\sqrt{5}}\))\(^2\) b)\(\sqrt{2-\sqrt{3}-\sqrt{2+\sqrt{3}}}\) c)\(\frac{\sqrt{10}+\sqrt{6}}{2\sqrt{5}+\sqrt{12}}\) d)\(\sqrt{8-2\sqrt{15}-\sqrt{8+2\sqrt{15}}}\) e)\(\sqrt{\left(1-\sqrt{2007}\right)^2}.\sqrt{2008+2\sqrt{2007}}\)
1. Rút gọn:
\(\sqrt{8-2\sqrt{7}}-\sqrt{9-2\sqrt{14}}\)
\(\sqrt{5-2\sqrt{6}}-\sqrt{11-4\sqrt{6}}\)
2. Tính:
a. 2 + \(\sqrt{17-4\sqrt{9}+4\sqrt{5}}\)
b. \(\sqrt{5\sqrt{3}+5\sqrt{48-10\sqrt{7}+4\sqrt{3}}}\)
c. \(\sqrt{4+\sqrt{10+2\sqrt{5}}}+\sqrt{4-\sqrt{10+2\sqrt{5}}}\)
3. CM:
a. \(\frac{x+y}{2}\) >= \(\sqrt{xy}\) với x, y >= 0
b. \(\frac{x}{y}+\frac{y}{x}\) >= 2 với x,y >= 0
c. a + b + 1 >= \(\sqrt{ab}\) + \(\sqrt{a}+\sqrt{b}\) với a,b >= 0.
bài 1: tính
a) \(\sqrt{1,2\cdot27}\) b) \(\sqrt{55\cdot77\cdot35}\)
c) (\(\sqrt{3}-\sqrt{2}\) )\(^2\) d) (3\(\sqrt{2}-1\))*(3\(\sqrt{2}+1\))
e) (\(\sqrt{6}+7\)) (\(\sqrt{3}-\sqrt{2}\)) i) \(\sqrt{\dfrac{1}{8}}\cdot\sqrt{2}\cdot\sqrt{125}\cdot\sqrt{\dfrac{1}{5}}\)
h) \(\sqrt{\sqrt{2}-1}\cdot\sqrt{\sqrt{2}}+1\)
bài 2: tính
a) \(\sqrt{9}-\sqrt{17}\cdot\sqrt{9}+\sqrt{17}\)
b) 2\(\sqrt{2}\left(\sqrt{3}-2\right)+\left(1+2\sqrt{2}\right)^2-2\sqrt{6}\)
c) \(\dfrac{\sqrt{6}+\sqrt{14}}{2\sqrt{3}+\sqrt{28}}\) d) \(\dfrac{\sqrt{10}+\sqrt{15}}{\sqrt{8}+\sqrt{12}}\)
e) \(\dfrac{\sqrt{15}-\sqrt{6}}{\sqrt{35}-\sqrt{14}}\) f) \(\dfrac{x+\sqrt{xy}}{9+\sqrt{xy}}\) (xy>0)
Bài 1 : Rút gọn biểu thức sau :
\(\frac{\sqrt{2}+\sqrt{3}+\sqrt{6}+\sqrt{8}+\sqrt{16}}{\sqrt{2}+\sqrt{3}+\sqrt{4}}\)
Bài 2 : Chứng minh đẳng thức sau :
\(\sqrt{8+2\sqrt{10+2\sqrt{5}}}.\sqrt{8-2\sqrt{10+2\sqrt{5}}}=2\sqrt{5}-2\)
Bài 3 : Cho biểu thức E = \(\left(\frac{\sqrt{x}+1}{\sqrt{x}-1}-\frac{\sqrt{x}-1}{\sqrt{x}+1}+4\sqrt{x}\right):\left(\sqrt{x}-\frac{1}{\sqrt{x}}\right)\)
a) Rút gọn biẻu thức E
b) Tính giá trị của E khi x = \(\left(4+\sqrt{15}\right)\left(\sqrt{10}-\sqrt{6}\right)\sqrt{4-\sqrt{15}}\)
Rút gon các biểu thức:
a)\(\frac{2\sqrt{15}-2\sqrt{10}+\sqrt{6}-3}{2\sqrt{5}-2\sqrt{10}-\sqrt{3}+\sqrt{6}}\)
b)\(\frac{\sqrt{2}+\sqrt{3}+\sqrt{6}+\sqrt{8}+\sqrt{16}}{\sqrt{2}+\sqrt{3}+\sqrt{4}}\)
c)\(\sqrt{9\left(3-a\right)^2}vớia>3\)
d)\(\sqrt{a^2.\left(a-2\right)^2}vớia< 0\)
a. \(\sqrt{21+6\sqrt{6}}+\sqrt{9+2\sqrt{18}}-2\sqrt{6+3\sqrt{3}}\)
b. \(\sqrt{6+2\sqrt{2\sqrt{3-\sqrt{4+2\sqrt{3}}}}}\)
c. \(\sqrt{4+\sqrt{15}}-\sqrt{7-3\sqrt{5}}\)
d.\(\sqrt{2+\sqrt{3}}-\sqrt{2-\sqrt{3}}\)
e. \(\sqrt{\frac{9}{4}-\sqrt{2}}+\sqrt{2}\)
Bài 1 : Rút gọn
a) \(\frac{\sqrt{6}+\sqrt{16}}{2\sqrt{3}+\sqrt{28}}\)
b) \(\frac{\sqrt{2}+\sqrt{3}+\sqrt{6}+\sqrt{8}+\sqrt{16}}{\sqrt{2}+\sqrt{3+\sqrt{4}}}\)
Bài 2: Chứng minh
a)\(\sqrt{9-\sqrt{17}}-\sqrt{9+\sqrt{17}}=8\)
b)\(2\sqrt{2}\left(\sqrt{3}-2\right)+\left(1+2\sqrt{2}\right)^2-2\sqrt{6}=9\)
Rút gọn
\(\sqrt{9-\sqrt{17}}.\sqrt{9+\sqrt{18}}\)
\(\left(\frac{1}{5-2\sqrt{6}}+\frac{2}{5+2\sqrt{6}}\right).\left(15+2\sqrt{6}\right)\)