Đặt \(A=\sqrt{4+\sqrt{15}}+\sqrt{4+\sqrt{15}}-2\sqrt{3-\sqrt{5}}\)
\(=2\left(\sqrt{4+\sqrt{15}}-\sqrt{3-\sqrt{5}}\right)\)
\(\Rightarrow\sqrt{2}A=2\left(\sqrt{8+\sqrt{15}}-\sqrt{6-2\sqrt{5}}\right)\)
\(=2\left(\sqrt{\left(\sqrt{3}+\sqrt{5}\right)^2}-\sqrt{\left(\sqrt{5}-1\right)^2}\right)\)
\(=2\left(\left|\sqrt{3}+\sqrt{5}\right|-\left|\sqrt{5}-1\right|\right)\)
\(=2\left(\sqrt{3}+\sqrt{5}-\sqrt{5}+1\right)\)
\(=2\sqrt{3}+2\)
\(\Rightarrow A=\sqrt{6}+\sqrt{2}\)
1. Tính
a. \(\left(4+\sqrt{15}\right)\left(\sqrt{10}-\sqrt{6}\right)\sqrt{4-\sqrt{15}}\)
b.\(\sqrt{3-\sqrt{5}}\left(\sqrt{10}-\sqrt{2}\right)\left(3+\sqrt{5}\right)\)
c.\(\dfrac{\sqrt{\sqrt{5}+2}+\sqrt{\sqrt{5}-2}}{\sqrt{\sqrt{5}+1}}-\sqrt{3-2\sqrt{2}}\)
Tính
a) \(\sqrt{\left(4-2\sqrt{3}\right).\left(13+4\sqrt{3}\right)}\)
b) \(\left(\sqrt{3}-2\right).\left(\sqrt{6}+\sqrt{2}\right).\sqrt{\sqrt{3}+2}\)
c)\(\left(3+\sqrt{5}\right).\left(\sqrt{10}-\sqrt{2}\right).\sqrt{3-\sqrt{5}}\)
d) \(\left(4+\sqrt{15}\right).\left(\sqrt{10}-\sqrt{6}\right).\sqrt{4-\sqrt{15}}\)
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Thực hiện phép tính:
a) ( \(4+\sqrt{15}\))\(\left(\sqrt{10}-\sqrt{6}\right)\sqrt{4-\sqrt{15}}\)
b)\(\sqrt{3-\sqrt{5}}\left(3+\sqrt{5}\right)\left(\sqrt{10}-\sqrt{2}\right)\)
c) \(\left(\sqrt{3}-\sqrt{2}+1\right)\left(\sqrt{3}-1\right)\)
d) \(\sqrt{2+\sqrt{3}}.\sqrt{2+\sqrt{2+\sqrt{3}}}.\sqrt{2+\sqrt{2+\sqrt{2+\sqrt{3}}}}.\sqrt{2-\sqrt{2+\sqrt{2+\sqrt{3}}}}\)
\(\sqrt{15+4\sqrt{6}+8\sqrt{3}+4\sqrt{2}}-2\sqrt{4+2\sqrt{3}}\)
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. \(\sqrt{\frac{9}{4}-\sqrt{2}}+\sqrt{2}\)
Tính
1) \(\sqrt{18}.\sqrt{2}\)
2) \(\sqrt{15^2-9^2}\)
3) \(\sqrt{46-6\sqrt{5}}-\sqrt{46+6\sqrt{5}}\)
4)\(\sqrt{21+6\sqrt{6}}-\sqrt{21-6\sqrt{6}}\)
5) \(\left(2+\sqrt{5}\right).\sqrt{9-4\sqrt{5}}\)
6)\(\left(3-\sqrt{2}\right).\sqrt{7+4\sqrt{3}}\)
7)\(\left(\sqrt{3}+\sqrt{5}\right).\sqrt{7-2\sqrt{10}}\)
8)\(\left(\sqrt{6}+\sqrt{10}\right).\sqrt{4-\sqrt{15}}\)
9) \(\sqrt{2}.\left(\sqrt{8}-\sqrt{32}+3\sqrt{18}\right)\)
10) \(\sqrt{2}\left(\sqrt{2}-\sqrt{3-\sqrt{5}}\right)\)
11) \(\sqrt{3}-\sqrt{2}-\sqrt{\left(\sqrt{3}+\sqrt{2}\right)^2}\)
12) \(\left(\sqrt{2}-\sqrt{3+\sqrt{5}}\right).\sqrt{2}+2\sqrt{5}\)
Tính
a)\(\sqrt{4-\sqrt{15}}.\sqrt{4+\sqrt{15}}\)
b)\(\sqrt{7-\sqrt{47}}.\sqrt{14+2\sqrt{47}}\)
c)\(\sqrt{4+\sqrt{10+2\sqrt{5}}}.\sqrt{4-\sqrt{10+2\sqrt{5}}}\)
Mọi người giúp mình với ạ. Mình xin chân thành cảm ơn!
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 = \(\left(4+\sqrt{15}\right)\left(\sqrt{10}-\sqrt{6}\right)\sqrt{4-\sqrt{15}}\)
Tính
B=\(\sqrt{3-\sqrt{5}}-\sqrt{3+\sqrt{5}}\)
C=\(\left(\sqrt{6}+\sqrt{10}\right).\sqrt{4-\sqrt{15}}\)
D=\(\left(3+\sqrt{5}\right).\left(\sqrt{10}-\sqrt{2}\right).\sqrt{3-\sqrt{5}}\)
