\(=\dfrac{(2+\sqrt3)(2+\sqrt7)}{(2+\sqrt7)(2-\sqrt7)} \\=\dfrac{4+2\sqrt7+2\sqrt3+\sqrt{21}}{-3} \\=\dfrac{-4-2\sqrt7-2\sqrt3-\sqrt{21}}{3}\)
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12 tháng 10 2021 lúc 19:29
* Thực hiện phép tính:
a. \(\dfrac{\sqrt{7}-5}{2}-\dfrac{6-2\sqrt{7}}{4}+\dfrac{6}{\sqrt{7}-2}-\dfrac{5}{4+\sqrt{7}}\)
b. \(\dfrac{2}{\sqrt{6}-2}+\dfrac{2}{\sqrt{6}+2}+\dfrac{5}{\sqrt{6}}\)
c. \(\dfrac{1}{\sqrt{3}+\sqrt{2}-\sqrt{5}}-\dfrac{1}{\sqrt{3}+\sqrt{2}+\sqrt{5}}\)
Tính:1) dfrac{1}{3-2sqrt{2}}+dfrac{1}{2+sqrt{5}}2) dfrac{1}{3-2sqrt{2}}-dfrac{1}{3+2sqrt{2}}3) dfrac{1}{sqrt{5}-sqrt{7}}+dfrac{2}{1-sqrt{7}}4) dfrac{1}{5+2sqrt{6}}-dfrac{1}{5-2sqrt{6}}5) -dfrac{1}{sqrt{2}-sqrt{3}}-dfrac{3}{sqrt{18}+2sqrt{3}}
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Tính:
1) \(\dfrac{1}{3-2\sqrt{2}}+\dfrac{1}{2+\sqrt{5}}\)
2) \(\dfrac{1}{3-2\sqrt{2}}-\dfrac{1}{3+2\sqrt{2}}\)
3) \(\dfrac{1}{\sqrt{5}-\sqrt{7}}+\dfrac{2}{1-\sqrt{7}}\)
4) \(\dfrac{1}{5+2\sqrt{6}}-\dfrac{1}{5-2\sqrt{6}}\)
5) \(-\dfrac{1}{\sqrt{2}-\sqrt{3}}\)\(-\dfrac{3}{\sqrt{18}+2\sqrt{3}}\)
Rút gọn các biểu thức sau:a. dfrac{8}{left(sqrt{5}+sqrt{3}right)^2} - dfrac{8}{left(sqrt{5}-sqrt{3}right)^2}b.dfrac{1}{4-3sqrt{2}} - dfrac{1}{4+3sqrt{2}}c.left(dfrac{sqrt{7}+3}{sqrt{7}-3}-dfrac{sqrt{7}-3}{sqrt{7}+3}right): sqrt{28}d.dfrac{3}{sqrt{6}-sqrt{3}}+dfrac{4}{sqrt{7}+sqrt{3}}
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Rút gọn các biểu thức sau:
a. \(\dfrac{8}{\left(\sqrt{5}+\sqrt{3}\right)^2}\) - \(\dfrac{8}{\left(\sqrt{5}-\sqrt{3}\right)^2}\)
b.\(\dfrac{1}{4-3\sqrt{2}}\) - \(\dfrac{1}{4+3\sqrt{2}}\)
c.\(\left(\dfrac{\sqrt{7}+3}{\sqrt{7}-3}-\dfrac{\sqrt{7}-3}{\sqrt{7}+3}\right)\): \(\sqrt{28}\)
d.\(\dfrac{3}{\sqrt{6}-\sqrt{3}}\)+\(\dfrac{4}{\sqrt{7}+\sqrt{3}}\)
dfrac{sqrt{3-sqrt{5}}left(3+sqrt{5}right)}{sqrt{10}+sqrt{2}}dfrac{10+2sqrt{10}}{sqrt{5}+sqrt{2}}+dfrac{8}{1-sqrt{5}}dfrac{5+sqrt{7}}{9-sqrt{23+8sqrt{7}}}+dfrac{5-sqrt{7}}{2+sqrt{16+6sqrt{7}}}dfrac{1}{sqrt{2}+sqrt{2+sqrt{3}}}+dfrac{1}{sqrt{2}-sqrt{2+sqrt{3}}}
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\(\dfrac{\sqrt{3-\sqrt{5}}\left(3+\sqrt{5}\right)}{\sqrt{10}+\sqrt{2}}\)
\(\dfrac{10+2\sqrt{10}}{\sqrt{5}+\sqrt{2}}\)+\(\dfrac{8}{1-\sqrt{5}}\)
\(\dfrac{5+\sqrt{7}}{9-\sqrt{23+8\sqrt{7}}}\)+\(\dfrac{5-\sqrt{7}}{2+\sqrt{16+6\sqrt{7}}}\)
\(\dfrac{1}{\sqrt{2}+\sqrt{2+\sqrt{3}}}\)+\(\dfrac{1}{\sqrt{2}-\sqrt{2+\sqrt{3}}}\)
Tính
a) \(\dfrac{3}{\sqrt{7}-4}+\dfrac{4+\sqrt{7}}{3}\)
b) \(\left(\dfrac{\sqrt{6}-\sqrt{2}}{\sqrt{3}-1}+\dfrac{1}{\sqrt{3}+\sqrt{2}}\right):\dfrac{1}{2\sqrt{3}}\)
Rút gọn các biểu thức saua) dfrac{1}{sqrt{3}}+dfrac{1}{3sqrt{2}}+dfrac{1}{sqrt{3}}dfrac{sqrt{3}-sqrt{2}}{2sqrt{3}} b) sqrt{12-3sqrt{7}}-sqrt{12+3sqrt{7}} c) sqrt[3]{dfrac{3}{4}}.sqrt[3]{dfrac{9}{16}}d) dfrac{sqrt[3]{54}}{sqrt[3]{-2}} e) sqrt[3]{5sqrt{2}+7}-sqrt[3]{5sqrt{2}-7}
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Rút gọn các biểu thức sau
a) \(\dfrac{1}{\sqrt{3}}+\dfrac{1}{3\sqrt{2}}+\dfrac{1}{\sqrt{3}}\dfrac{\sqrt{3}-\sqrt{2}}{2\sqrt{3}}\) b) \(\sqrt{12-3\sqrt{7}}-\sqrt{12+3\sqrt{7}}\) c) \(\sqrt[3]{\dfrac{3}{4}}.\sqrt[3]{\dfrac{9}{16}}\)
d) \(\dfrac{\sqrt[3]{54}}{\sqrt[3]{-2}}\) e) \(\sqrt[3]{5\sqrt{2}+7}-\sqrt[3]{5\sqrt{2}-7}\)
a : \(\sqrt{5+2\sqrt{6}}-\sqrt{\left(\sqrt{2}-\sqrt{3}\right)^2}\)
b : \(\dfrac{\sqrt{7}-2\sqrt{7}}{2-\sqrt{7}}+\dfrac{6}{\sqrt{7}+1}+\left(3\sqrt{2}-2\sqrt{3}\right)\left(3\sqrt{2}+2\sqrt{3}\right)\)
Thực hiện phép tính ( rút gọn biểu thức )a) dfrac{1}{2sqrt{2}-3}+dfrac{1}{2sqrt{2}+3} b) dfrac{sqrt{2}}{2sqrt{2}+sqrt{7}}+dfrac{sqrt{2}}{2sqrt{2}-sqrt{7}}c) dfrac{1}{2-sqrt{5}}-dfrac{2}{2+sqrt{5}}
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Thực hiện phép tính ( rút gọn biểu thức )
a) \(\dfrac{1}{2\sqrt{2}-3}\)+\(\dfrac{1}{2\sqrt{2}+3}\) b) \(\dfrac{\sqrt{2}}{2\sqrt{2}+\sqrt{7}}\)+\(\dfrac{\sqrt{2}}{2\sqrt{2}-\sqrt{7}}\)
c) \(\dfrac{1}{2-\sqrt{5}}\)-\(\dfrac{2}{2+\sqrt{5}}\)
THỰC HIỆN PHÉP TÍNH1,sqrt{3+sqrt{5}}.sqrt{2}2,sqrt{3-sqrt{5}.sqrt{8}}3,(sqrt{dfrac{3}{4}}-sqrt{3}+5sqrt{dfrac{4}{3})}.sqrt{12}4,(sqrt{dfrac{1}{7}}-sqrt{dfrac{16}{7}}+sqrt{7}):sqrt{7}5, sqrt{36-12sqrt{5}}:sqrt{6}6,sqrt{3-sqrt{5}:}sqrt{2}
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THỰC HIỆN PHÉP TÍNH
1,\(\sqrt{3+\sqrt{5}}.\sqrt{2}\)
2,\(\sqrt{3-\sqrt{5}.\sqrt{8}}\)
3,\((\sqrt{\dfrac{3}{4}}-\sqrt{3}+5\sqrt{\dfrac{4}{3})}.\sqrt{12}\)
4,\((\sqrt{\dfrac{1}{7}}-\sqrt{\dfrac{16}{7}}+\sqrt{7}):\sqrt{7}\)
5, \(\sqrt{36-12\sqrt{5}}:\sqrt{6}\)
6,\(\sqrt{3-\sqrt{5}:}\sqrt{2}\)
tính
A=\(\left(1-\sqrt{7}\right).\dfrac{\sqrt{7}+7}{2\sqrt{7}}\)
B=\(3\sqrt{3}+4\sqrt{12}-5\sqrt{27}\)
C=\(\sqrt{32}-\sqrt{50}+\sqrt{18}\)
D=\(\sqrt{72}+\sqrt{4\dfrac{1}{2}}-\sqrt{32}-\sqrt{162}\)
E=\(\dfrac{1}{2}\sqrt{48}-2\sqrt{75}-\dfrac{\sqrt{33}}{\sqrt{11}}+5\sqrt{1\dfrac{1}{3}}\)