RÚT GỌN:
1)\(\sqrt{3+2\sqrt{2}}\) +\(\sqrt{6-4\sqrt{2}}\)
2)\(\frac{a\sqrt{a}-8+2a-4\sqrt{a}}{a-4}\)
\(\sqrt{3+2\sqrt{2}}\) +\(\sqrt{6-4\sqrt{2}}\)
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời. RÚT GỌN: 1)\(\sqrt{3+2\sqrt{2}}\) +\(\sqrt{6-4\sqrt{2}}\) 2)\(\frac{a\sqrt{a}-8+2a-4\sqrt{a}}{a-4}\) \(A=\frac{a\left(\sqrt{a}+2\right)-4\left(\sqrt{a}+2\right)}{a-4}=\frac{\left(a-4\right)\left(\sqrt{a}+2\right)}{a-4}=\sqrt{a}+2\) \(B=\frac{12\sqrt{6}}{\sqrt{\sqrt{\left(\sqrt{6}+1\right)^2}-\sqrt{\left(\sqrt{6}-1\right)^2}}}=\frac{12\sqrt{6}}{\sqrt{2}}=12\sqrt{3}\) C k thấy đề \(A=\frac{a\sqrt{a}-8+2a-4\sqrt{a}}{a-4}=\frac{\left(a\sqrt{a}-4\sqrt{a}\right)+\left(2a-8\right)}{a-4}=\frac{\left(a-4\right)\left(\sqrt{a}+2\right)}{a-4}=\sqrt{a}+2\) \(B=\frac{12\sqrt{6}}{\sqrt{7+2\sqrt{6}}-\sqrt{7-2\sqrt{6}}}=\frac{12\sqrt{6}}{\sqrt{1+6+2\sqrt{6}}-\sqrt{1+6-2\sqrt{6}}}\) \(=\frac{12\sqrt{6}}{\sqrt{\left(1+\sqrt{6}\right)^2}-\sqrt{\left(\sqrt{6}-1\right)^2}}=\frac{12\sqrt{6}}{1+\sqrt{6}-\sqrt{6}+1}=6\sqrt{6}\) \(C=\frac{\sqrt{c^2+2c+1}}{\left|c\right|-1}=\frac{\left|c+1\right|}{\left|c\right|-1}\) 1) \(A^2=2+2.\frac{\sqrt{\left(8+\sqrt{15}\right)\left(8-\sqrt{15}\right)}}{2}\) \(2+\sqrt{64-15}=2+\sqrt{49}=2+7=9\) mà A>0 => A=3 2) \(A=\sqrt{4-\sqrt{15}}\left(4+\sqrt{15}\right)\left(\sqrt{10}-\sqrt{6}\right).\) \(A=\sqrt{\left(4-\sqrt{15}\right)\left(4+\sqrt{15}\right)}\sqrt{4+\sqrt{15}}\left(\sqrt{10}-\sqrt{6}\right).\) \(A=\sqrt{4+\sqrt{15}}\left(\sqrt{10}-\sqrt{6}\right).\) \(A^2=\left(4+\sqrt{15}\right)\left(16-4\sqrt{15}\right)\) \(=4\left(4+\sqrt{15}\right)\left(4-\sqrt{15}\right)=4\) Mà A >0 => A=2 Mà 4>3 => \(\sqrt{4}=2>\sqrt{3}\) => \(A>\sqrt{3}\) a) Ta có: \(\left(\sqrt{8}-3\sqrt{2}+\sqrt{10}\right)\sqrt{2}-\sqrt{5}\) \(=\left(-\sqrt{2}+\sqrt{10}\right)\sqrt{2}-\sqrt{5}\) \(=-2+2\sqrt{5}-\sqrt{5}\) \(=-2+\sqrt{5}\) b) \(\left(\frac{1}{2}\sqrt{\frac{1}{2}}-\frac{3}{2}\sqrt{2}+\frac{4}{5}\sqrt{200}\right)\div\frac{1}{8}\) \(=\left(\frac{\sqrt{2}}{4}-\frac{3\sqrt{2}}{2}+8\sqrt{2}\right)\cdot8\) \(=\frac{27\sqrt{2}}{4}\cdot8\) \(=54\sqrt{2}\) \(b,\frac{2+\sqrt{3}}{1-\sqrt{4-2\sqrt{3}}}+\frac{2-\sqrt{3}}{1+\sqrt{4+2\sqrt{3}}}\) \(=\frac{2+\sqrt{3}}{1-\sqrt{3-2\sqrt{3}+1}}+\frac{2-\sqrt{3}}{1+\sqrt{3+2\sqrt{3}+1}}\) \(=\frac{2+\sqrt{3}}{1-\sqrt{\left(\sqrt{3}-1\right)^2}}+\frac{2-\sqrt{3}}{1+\sqrt{\left(\sqrt{3}+1\right)^2}}\) \(=\frac{2+\sqrt{3}}{1-\left(\sqrt{3}-1\right)}+\frac{2-\sqrt{3}}{1+\sqrt{3}+1}\) \(=\frac{2+\sqrt{3}}{2-\sqrt{3}}+\frac{2-\sqrt{3}}{2+\sqrt{3}}\) \(=\frac{\left(2+\sqrt{3}\right)^2}{\left(2-\sqrt{3}\right)\left(2+\sqrt{3}\right)}+\frac{\left(2-\sqrt{3}\right)^2}{\left(2-\sqrt{3}\right)\left(2+\sqrt{3}\right)}\) \(=\frac{4+4\sqrt{3}+3+4-4\sqrt{3}+3}{4-3}\) \(=14\) \(a,\frac{\sqrt{2}+\sqrt{3}+\sqrt{6}+\sqrt{8}+\sqrt{16}}{\sqrt{2}+\sqrt{3}+\sqrt{4}}\) \(=\frac{\sqrt{2}+\sqrt{3}+4+\sqrt{6}+\sqrt{8}}{\sqrt{2}+\sqrt{3}+2}\) \(=\frac{\sqrt{2}+\sqrt{3}+2}{\sqrt{2}+\sqrt{3}+2}+\frac{\sqrt{2}.\sqrt{2}+\sqrt{2}.\sqrt{3}+\sqrt{2}.2}{\sqrt{2}+\sqrt{3}+2}\) \(=1+\frac{\sqrt{2}\left(\sqrt{2}+\sqrt{3}+2\right)}{\sqrt{2}+\sqrt{3}+2}\) \(=1+\sqrt{2}\)