A = \(\sqrt{4+\sqrt{15}}\) => A. \(\sqrt{2}\) =\(\sqrt{2}.\sqrt{4+\sqrt{15}}\) = \(\sqrt{8+2\sqrt{15}}\)
= \(\sqrt{\left(\sqrt{3}\right)^2+2.\sqrt{3}\sqrt{5}+\left(\sqrt{5}\right)^2}\) =\(\sqrt{\left(\sqrt{3}+\sqrt{5}\right)^2}\)= \(\sqrt{3}+\sqrt{5}\)
=> A = \(\dfrac{\sqrt{3}+\sqrt{5}}{\sqrt{2}}\)
Tính:
a) \(A=\left(\sqrt{6}+\sqrt{10}\right)-\sqrt{4-\sqrt{15}}\)
b) \(B=\left(3+\sqrt{5}\right)\left(\sqrt{10}-\sqrt{2}\right).\sqrt{3-\sqrt{15}}\)
c) \(C=\left(4+\sqrt{15}\right)\left(\sqrt{10}-\sqrt{6}\right).\sqrt{4-\sqrt{15}}\)
Rút gọn: A = \(\sqrt{4 +\sqrt{15}} + \sqrt{4 -\sqrt{15}} - 2 \sqrt{3- \sqrt{5}}\)
\(\left(4+\sqrt{15}\right)\left(\sqrt{10}-\sqrt{6}\right)\sqrt{4-\sqrt{15}}\)
Tính B=\(\sqrt{4+2\sqrt{3}}-\sqrt{4-2\sqrt{3}}\)
C=\(\sqrt{94-42\sqrt{5}}-\sqrt{94+42\sqrt{5}}\)
D=\(\left(4+\sqrt{15}\right)\left(\sqrt{10}-\sqrt{6}\right)\sqrt{4-\sqrt{15}}\)
E=\(\sqrt{6+\sqrt{24}+\sqrt{12}+\sqrt{8}}-\sqrt{3}-\sqrt{2}-15\)
F=\(\sqrt{5}-\sqrt{3-\sqrt{29-12\sqrt{5}}}\)
\(\left(4+\sqrt{15}\right)\left(\sqrt{10}-\sqrt{6}\right)\left(\sqrt{4-\sqrt{15}}\right)\)
Tính giá trị biểu thức : \(A=\sqrt{2+\sqrt[3]{3+\sqrt[4]{4+\sqrt[5]{5+...+\sqrt[14]{14+\sqrt[15]{15}}}}}}\)
Rút gọn biểu thức
a. \(A=\sqrt{\sqrt{5}-\sqrt{3-\sqrt{29-\sqrt{12\sqrt{5}}}}}\)
b. \(B=\left(4+\sqrt{15}\right)\left(\sqrt{10}-\sqrt{6}\right)\left(\sqrt{4-\sqrt{15}}\right)\)
\(\left(5+4\sqrt{2}\right)\left(3+2\sqrt{1+\sqrt{2}}\right)\left(3-2\sqrt{1+\sqrt{2}}\right)\\ \\ \\ \sqrt{\frac{9}{4}-\sqrt{2}}\\ \\ \\ Sosanh2\sqrt{27}va\sqrt{147}\\ \\ \\ 2\sqrt{15}va\sqrt{59}\\ \\ \\ 2\sqrt{2}-1va2\\ \\ \\ \frac{\sqrt{3}}{2}va1\\ \\ \\ -\frac{\sqrt{10}}{2}va-2\sqrt{5}\\ \\ \\ \sqrt{6}-1va3\\ \\ \\ 2\sqrt{5}-5\sqrt{2}va1\\ \\ \\ \frac{\sqrt{8}}{3}va\frac{3}{4}\\ \\ \\ -2\sqrt{6}va-\sqrt{23}\\ \\ \\ 2\sqrt{6}-2va3\\ \\ \\ \sqrt{111}-7va4\)
Xếp theo thứ tự tăng dần: \(21,2\sqrt{7},15\sqrt{3},-\sqrt{123}\) ; \(28\sqrt{2},\sqrt{14},2\sqrt{147},36\sqrt{4}\)
giảm dần: \(6\sqrt{\frac{1}{4}},4\sqrt{\frac{1}{2}},-\sqrt{132},2\sqrt{3},\sqrt{\frac{15}{5}}\); \(-27,4\sqrt{3},16\sqrt{5},21\sqrt{2}\)
Cho A = \(\left(\frac{\sqrt{a}+1}{\sqrt{a}-1}-\frac{\sqrt{a}-1}{\sqrt{a}+1}+4\sqrt{a}\right)\left(\sqrt{a}-\frac{1}{\sqrt{a}}\right)\)
a) Rút gọn A
b) Tính A với a = \(\left(4+\sqrt{15}\right)\left(\sqrt{10}-\sqrt{6}\right)\sqrt{4-\sqrt{15}}\)
Gỉai giúp mk vs
\(\sqrt{21-6\sqrt{6}}\)
\(\sqrt{14-6\sqrt{5}}+\sqrt{14+6\sqrt{5}}\)
\(\left(3-\sqrt{2}\right)\sqrt{7+4\sqrt{3}}\)
\(\sqrt{13+4\sqrt{10}}+\sqrt{13-4\sqrt{10}}\)
\(\sqrt{6}\left(\sqrt{26+15\sqrt{3}}+\sqrt{26-15\sqrt{3}}\right)\)
