=6+3căn 45-4căn 405
=6+9căn 5-36căn 5
=6-27căn 5
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Bài 7: Biến đối đơn giản biểu thức chứa căn bậc hai (Tiếp theo)
Các câu hỏi tương tự
1. dfrac{-2}{sqrt{3}-1}2. dfrac{5}{1-sqrt{6}}3. dfrac{2+sqrt{5}}{2-sqrt{5}}4. dfrac{1}{5+2sqrt{6}}5. dfrac{sqrt{5}+2}{sqrt{5}-2}6. dfrac{5sqrt{2}-2sqrt{5}}{sqrt{2}-sqrt{5}}7. dfrac{sqrt{20}-3sqrt{10}}{3-sqrt{2}}8. dfrac{6-2sqrt{5}}{3+sqrt{5}}9. dfrac{9+4sqrt{5}}{sqrt{5}+2}
Đọc tiếp
1. \(\dfrac{-2}{\sqrt{3}-1}\)
2. \(\dfrac{5}{1-\sqrt{6}}\)
3. \(\dfrac{2+\sqrt{5}}{2-\sqrt{5}}\)
4. \(\dfrac{1}{5+2\sqrt{6}}\)
5. \(\dfrac{\sqrt{5}+2}{\sqrt{5}-2}\)
6. \(\dfrac{5\sqrt{2}-2\sqrt{5}}{\sqrt{2}-\sqrt{5}}\)
7. \(\dfrac{\sqrt{20}-3\sqrt{10}}{3-\sqrt{2}}\)
8. \(\dfrac{6-2\sqrt{5}}{3+\sqrt{5}}\)
9. \(\dfrac{9+4\sqrt{5}}{\sqrt{5}+2}\)
Rút gọn biểu thức
\(a.\dfrac{\sqrt{5}-2\sqrt{3}}{\sqrt{5}+\sqrt{3}}-\dfrac{2\sqrt{5}+\sqrt{3}}{\sqrt{5}-\sqrt{3}}\)
\(b.x\sqrt{2x+2}+\left(x+1\right)\sqrt{\dfrac{2}{x+1}}-4\sqrt{\dfrac{x+1}{2}}\)
Bài 1 Rút gọn biểu thức:
a) \(\dfrac{\sqrt{3-\sqrt{5}.}\left(3+\sqrt{5}\right)}{\sqrt{10}+\sqrt{2}}\)
b) \(\dfrac{4}{\sqrt{3}+1}+\dfrac{1}{\sqrt{3}-1}+\dfrac{6}{\sqrt{3}-3}\)
Giải 5 câu sau:
1. \(\dfrac{\sqrt{5}+2}{\sqrt{5}-2}\)
2. \(\dfrac{5\sqrt{2}-2\sqrt{5}}{\sqrt{2}-\sqrt{5}}\)
3. \(\dfrac{\sqrt{20}-3\sqrt{10}}{3-\sqrt{5}}\)
4. \(\dfrac{6-2\sqrt{5}}{3+\sqrt{5}}\)
5. \(\dfrac{9+4\sqrt{5}}{\sqrt{5}+2}\)
Tính
a)\(\frac{\sqrt{15}-\sqrt{5}}{\sqrt{3}-1}-\frac{5-2\sqrt{5}}{2\sqrt{5}-4}\)
b)\(\frac{2\sqrt{8}-\sqrt{12}}{\sqrt{3}-1}-\frac{\sqrt{5}+\sqrt{27}}{\sqrt{30}-\sqrt{2}}\)
c)\(\frac{2}{\sqrt{3}-1}-\frac{2}{\sqrt{3}+1}\)
A = \(\dfrac{4+\sqrt{3}}{\sqrt{1}+\sqrt{3}}+\dfrac{6+\sqrt{8}}{\sqrt{3}+\sqrt{5}}+...+\dfrac{2n+\sqrt{n^2-1}}{\sqrt{n-1}+\sqrt{n+1}}+\dfrac{240+\sqrt{14399}}{\sqrt{119}+\sqrt{121}}\)
B= \(\dfrac{1}{\sqrt{2}-\sqrt{3}}-\dfrac{1}{\sqrt{3}-\sqrt{4}}+\dfrac{1}{\sqrt{4}-\sqrt{5}}-....+\dfrac{1}{\sqrt{100}-\sqrt{101}}\)
Rút gọn :
\(\dfrac{1}{\sqrt{1}-\sqrt{2}}-\dfrac{1}{\sqrt{2}-\sqrt{3}}+\dfrac{1}{\sqrt{3}-\sqrt{4}}-\dfrac{1}{\sqrt{4}-\sqrt{5}}+\dfrac{1}{\sqrt{5}-\sqrt{6}}-\dfrac{1}{\sqrt{6}-\sqrt{7}}+\dfrac{1}{\sqrt{7}-\sqrt{8}}-\dfrac{1}{\sqrt{8}-\sqrt{9}}\)
Rút gọn các biểu thức :
a) \(\dfrac{2}{\sqrt{3}-1}-\dfrac{2}{\sqrt{3}+1}\)
b) \(\dfrac{5}{12\left(2\sqrt{5}+3\sqrt{2}\right)}-\dfrac{5}{12\left(2\sqrt{5}-3\sqrt{2}\right)}\)
c) \(\dfrac{5+\sqrt{5}}{5-\sqrt{5}}+\dfrac{5-\sqrt{5}}{5+\sqrt{5}}\)
d) \(\dfrac{\sqrt{3}}{\sqrt{\sqrt{3+1}}-1}-\dfrac{\sqrt{3}}{\sqrt{\sqrt{3+1}}+1}\)
Tính:
a/ frac{2}{sqrt{3}-1}+frac{3}{sqrt{3}-2}+frac{12}{3-sqrt{3}}
b/ frac{1}{sqrt{3}-sqrt{2}}-frac{2}{sqrt{7}+sqrt{5}}-frac{3}{sqrt{5}-sqrt{2}}+frac{4}{sqrt{7}+sqrt{3}}
c/ frac{sqrt{14}-sqrt{17}}{1-sqrt{2}}
d/ frac{3sqrt{2}-3}{sqrt{2}-1}
e/ frac{5sqrt{a}-sqrt{ab}}{sqrt{b}-5}
Đọc tiếp
Tính:
a/ \(\frac{2}{\sqrt{3}-1}+\frac{3}{\sqrt{3}-2}+\frac{12}{3-\sqrt{3}}\)
b/ \(\frac{1}{\sqrt{3}-\sqrt{2}}-\frac{2}{\sqrt{7}+\sqrt{5}}-\frac{3}{\sqrt{5}-\sqrt{2}}+\frac{4}{\sqrt{7}+\sqrt{3}}\)
c/ \(\frac{\sqrt{14}-\sqrt{17}}{1-\sqrt{2}}\)
d/ \(\frac{3\sqrt{2}-3}{\sqrt{2}-1}\)
e/ \(\frac{5\sqrt{a}-\sqrt{ab}}{\sqrt{b}-5}\)
chỉ cần đưa về dạng hằng đảng thức thôi , xin cam ơn mọi người
1,sqrt{26+15sqrt{3}}
2,sqrt{8-2sqrt{15}}-sqrt{23-4sqrt{5}}
3,sqrt{12-3sqrt{7}}-sqrt{12-3sqrt{7}}
4,sqrt{7-2sqrt{10}}-sqrt{7+2sqrt{10}}
5,sqrt{4+sqrt{10+2sqrt{5}}}+sqrt{4-sqrt{10+2sqrt{5}}}
6,3sqrt{3}+4sqrt{12}-5sqrt{27}
7,sqrt{32}-sqrt{50}+sqrt{18}
8,sqrt{72}+sqrt{4dfrac{1}{2}}-sqrt{32}-sqrt{162}
9,dfrac{1}{2}sqrt{48}-2sqrt{75}-dfrac{sqrt{33}}{sqrt{11}}+5sqrt{1dfrac{1}{3}}
Đọc tiếp
chỉ cần đưa về dạng hằng đảng thức thôi , xin cam ơn mọi người
1,\(\sqrt{26+15\sqrt{3}}\)
2,\(\sqrt{8-2\sqrt{15}}-\sqrt{23-4\sqrt{5}}\)
3,\(\sqrt{12-3\sqrt{7}}-\sqrt{12-3\sqrt{7}}\)
4,\(\sqrt{7-2\sqrt{10}}-\sqrt{7+2\sqrt{10}}\)
5,\(\sqrt{4+\sqrt{10+2\sqrt{5}}}+\sqrt{4-\sqrt{10+2\sqrt{5}}}\)
6,\(3\sqrt{3}+4\sqrt{12}-5\sqrt{27}\)
7,\(\sqrt{32}-\sqrt{50}+\sqrt{18}\)
8,\(\sqrt{72}+\sqrt{4\dfrac{1}{2}}-\sqrt{32}-\sqrt{162}\)
9,\(\dfrac{1}{2}\sqrt{48}-2\sqrt{75}-\dfrac{\sqrt{33}}{\sqrt{11}}+5\sqrt{1\dfrac{1}{3}}\)