Cm
\(\sqrt{a+4\sqrt{a-2}+2}+\sqrt{a-4\sqrt{a-2}+2}=4\) ( vs 2 ≤ a ≤ 6)
Tính:
a, A = \(\sqrt{3+2\sqrt{2}}-\sqrt{6-4\sqrt{2}}\)
b, B = \(\sqrt{6-2\sqrt{5}+\sqrt{6+2\sqrt{5}}}\)
c, C = \(\sqrt{1+2\sqrt{1+2\sqrt{3+2\sqrt{2}}}}\)
d, D = \(\sqrt{6+2\sqrt{5-\sqrt{13+4\sqrt{3}}}}\)
e, E = \(\sqrt{13+30\sqrt{2+\sqrt{9+4\sqrt{2}}}}\)
Chứng minh đẳng thức:
\(\sqrt{a+4\sqrt{a-2}+2}+\sqrt{a-4\sqrt{a-2}+2}=4\) ( với \(2\le a\le6\) ).
bài 1) rút gọn
1) 5√\(\frac{1}{5}\) 2)\(\frac{12}{5}\)√\(\frac{5}{4}\) 3)\(\frac{30}{5\sqrt{6}}\) 4) \(\frac{20}{2\sqrt{5}}\) 5)\(\frac{2-\sqrt{2}}{\sqrt{2}}\) 6) \(\frac{11+\sqrt{11}}{1+\sqrt{ }11}\) 7) \(\frac{\sqrt{21-\sqrt{7}}}{1-\sqrt{3}}\) 8)\(\frac{\sqrt{2+\sqrt{3}}}{2+\sqrt{6}}\) 9)\(\frac{\sqrt{10-\sqrt{2}}}{\sqrt{5-}1}\) 10)\(\frac{2\sqrt{3}-3\sqrt{2}}{\sqrt{3}-\sqrt[]{2}}\)
bài 2) với các biểu thức đã cho là có nghĩa và rút gọn
1)\(\frac{x-\sqrt{x}}{\sqrt{x}-1}\) 2)\(\frac{x\sqrt{x}-2x}{2-\sqrt{x}}\) 3) \(\frac{x\sqrt{y}-y\sqrt{x}}{\sqrt{x}-\sqrt{y}}\) 4) \(\frac{a\sqrt{b}-\sqrt{a}}{\sqrt{b}-b\sqrt{a}}\) 5) \(\frac{a-1}{\sqrt{a}+1}\) 6) \(\frac{4-x}{2\sqrt{x}-x}\) 7)\(\frac{a+1+2\sqrt{a}}{1+\sqrt{a}}\) 8)\(\frac{3\sqrt{x}-x}{3+2\sqrt{3x}-x}\) 9)\(\frac{y+12-4\sqrt{3y}}{y-12}\) 10)\(\frac{4\sqrt{x}-x-4}{x-4}\) 11)\(\frac{x+y-2\sqrt{xy}}{x\sqrt{y}-y\sqrt{x}}\)
Câu1: Rút gọn
\(a,x+\sqrt{\left(x+2\right)^2}\cdot\left(x-2\right)\\ b,\sqrt{m^2-6m+9-2m}\left(x>3\right)\\ c,1+\sqrt{\frac{\left(x-1\right)^2}{x-1}}\\ d,\sqrt{x+4\sqrt{x-4}}+\sqrt{x-4\sqrt{x-4}}\)
Câu 2: So sánh
\(a,3và\sqrt{5}\\ \\ \\ b,2\sqrt{2}và3\sqrt{2}\\ \\ \\ c,-4\sqrt{5}và-6\sqrt{6}\\ \\ \\ d,2\sqrt{3}-5và\sqrt{3}-4\\ \\ \\e,A=\sqrt{2006}-\sqrt{2005}và\\ B=\sqrt{2005}-\sqrt{2004}\)
Câu 3: Rút gọn
\(a,\sqrt{16-2\sqrt{55}}\\ \\ \\ \\ \\ \\ \\ \\ \\ b,\sqrt{14-6\sqrt{5}}\\ \\ \\ \\ \\ \\ \\ \\ \\ c,\sqrt{36+12\sqrt{5}}\\ \\ \\ \\ \\ \\ \\ \\ \\ d,\sqrt{29+12\sqrt{5}}\)
Câu4: Tìm đkxđ
\(a,\sqrt{x^2-9}\\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ b,\sqrt{x^2-3x+2}\)
\(c,\frac{\sqrt{x+3}}{\sqrt{5-x}}\\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ d,\sqrt{\frac{x+3}{5-x}}\)
Chứng minh đẳng thức:
(\(1-\frac{4}{a}\))(\(\frac{\sqrt{a}-1}{\sqrt{a}+2}\)-\(\frac{\sqrt{a}+1}{\sqrt{a}-2}\)) =\(\frac{-6}{\sqrt{a}}\) với a > 0 và a ≠ 4
Tính :
a) \(\sqrt{3-2\sqrt{2}}+\sqrt{3+2\sqrt{2}}\)
b) \(\sqrt{9-4\sqrt{5}}+\sqrt{6+2\sqrt{5}}\)
c) \(\sqrt{9-4\sqrt{2}}-\sqrt{11+6\sqrt{2}}\)
d) \(\sqrt{12+8\sqrt{2}}+\sqrt{6-4\sqrt{2}}\)
Thực hiện phép tính
a, \(\sqrt{5+2\sqrt{6}}-\sqrt{5-2\sqrt{6}}\)
b,\(\sqrt{4-2\sqrt{3}}+\sqrt{4+2\sqrt{3}}\)
c, \(\sqrt{17-12\sqrt{2}}+\sqrt{9+4\sqrt{2}}\)
d, \(\sqrt{6+2\sqrt{2}\sqrt{3-\sqrt{4+2\sqrt{3}}}}\)
rút gọn
a, \(\sqrt{12-2\sqrt{11}}-\sqrt{11}\)
b, \(x-4+\sqrt{16-8x+x^2}\left(x>4\right)\)
c, \(\sqrt{3-2\sqrt{2}+}\sqrt{3+2\sqrt{2}}\)
d, \(A=\dfrac{a\sqrt{a}-8+2a-4\sqrt{a}}{a-4}\)
Rút gọn biểu thức
a)A=\(\sqrt{3-2\sqrt{2}}\)
b)B=\(\sqrt{3-2\sqrt{2}}-\sqrt{6+4\sqrt{2}}\)
c)C=\(\sqrt{2+\sqrt{3}}+\sqrt{2-\sqrt{3}}\)