a)
Ta có :
\(\sqrt{0,16}\) + \(\sqrt{\frac{4}{25}}\) = \(\sqrt{\left(0,4^2\right)}\) + \(\sqrt{\left(\frac{2}{5}\right)^2}\) = 0,4 + \(\frac{2}{5}\) = \(\frac{2}{5}+\frac{2}{5}\) = \(\frac{4}{5}\)
b)
Ta có :
\(\sqrt{3\frac{3}{16}}\) - \(\sqrt{0,36}\) = \(\sqrt{\left(\frac{7}{4}\right)^2}\) - \(\sqrt{\left(0,6^2\right)}\) = \(\frac{7}{4}-\frac{3}{5}=\frac{23}{20}\)
a. Chứng minh : \(\frac{1}{\left(n+1\right)\sqrt{n}+n\sqrt{n+1}}=\frac{1}{\sqrt{n}}-\frac{1}{\sqrt{n+1}}\)
b. Áp dụng : Tính giá trị của biểu thức :
\(M=\frac{1}{2\sqrt{1}+1\sqrt{2}}+\frac{1}{3\sqrt{2}+2\sqrt{3}}+\frac{1}{4\sqrt{3}+3\sqrt{4}}+...+\frac{1}{25\sqrt{24}+24\sqrt{25}}\)
cảm ơn các bạn trước nhé!
Rút gọn:
a)\(\frac{\sqrt{6}+\sqrt{14}}{2\sqrt{3}+\sqrt{28}}\)
b)\(\frac{\sqrt{2}+\sqrt{3}+\sqrt{6}+\sqrt{8}+\sqrt{16}}{\sqrt{2}+\sqrt{3}+\sqrt{4}}\)
Rút gọn:
a) \(\frac{\sqrt{6+\sqrt{14}}}{2\sqrt{3+\sqrt{28}}}\)
b) \(\frac{\sqrt{2}+\sqrt{3}+\sqrt{6}+\sqrt{8}+\sqrt{16}}{\sqrt{2}+\sqrt{3}+\sqrt{4}}\)
Thực hiện phép tính
a, \(\sqrt{12-3\sqrt{7}-\sqrt{12+3\sqrt{7}}}\)
b, \(\sqrt{125}-4\sqrt{45}+3\sqrt{20}-\sqrt{80}\)
c, \(2\sqrt{\frac{27}{4}}-\sqrt{\frac{48}{9}}-\frac{2}{5}\sqrt{\frac{75}{16}}\)
d , \(\left(\sqrt{99}-\sqrt{18}-\sqrt{11}\right)\sqrt{11}+3\sqrt{22}\)
có ai giúp tui
\(\left(\sqrt{6}+\sqrt{2}\right)\left(\sqrt{3}-2\right)\sqrt{3}+2\)
\(\frac{2\sqrt{8}-\sqrt{12}}{\sqrt{18}-\sqrt{48}}-\frac{\sqrt{5}+\sqrt{27}}{\sqrt{30}+\sqrt{162}}\)
\(2\sqrt{5}-\sqrt{125}-\sqrt{80}+\sqrt{605}\)
\(\sqrt{8\sqrt{3}-2\sqrt{25\sqrt{12}}+8\sqrt{\sqrt{192}}}\)
2. cho A=\(\sqrt{15a^2-8a\sqrt{15}+16}\)
a. Rút gọn A
b. Tính A khi a=\(\sqrt{\frac{3}{5}}+\sqrt{\frac{5}{3}}\)
Tính các tổng
a. \(A=\frac{1}{\sqrt{1}-\sqrt{2}}-\frac{1}{\sqrt{2}-\sqrt{3}}+\frac{1}{\sqrt{3}-\sqrt{4}}-\frac{1}{\sqrt{4}-\sqrt{5}}+....+\frac{1}{\sqrt{2007}-\sqrt{2008}}\)
b. \(B=\frac{1}{2\sqrt{1}+1\sqrt{2}}+\frac{1}{3\sqrt{2}+2\sqrt{3}}+\frac{1}{4\sqrt{3}+3\sqrt{4}}+...+\frac{1}{121\sqrt{120}+120\sqrt{121}}\)
Mọi người giúp tớ với nhé!! Cảm ơn trước nha!!
Rút gọn biểu thức
a)\(\frac{a-1}{\sqrt[3]{a^2}+\sqrt[3]{a}+1}\)\
b)\(\left(12\sqrt[3]{2}+\sqrt[3]{16}-2\sqrt[3]{2}\right)\left(5\sqrt[3]{4}-3\sqrt[3]{\frac{1}{2}}\right)\)
rút gọn
P=\(\left(\frac{3\sqrt{a}}{\sqrt{a}+4}+\frac{\sqrt{a}}{\sqrt{a}-4}+\frac{4\left(a+2\right)}{16-a}\right):\left(1-\frac{2\sqrt{a}+5}{\sqrt{a}+4}\right)\)
Thực hiện các phép tính sau
a, \(\frac{\sqrt{7}-5}{2}-\frac{6-2\sqrt{7}}{4}+\frac{6}{\sqrt{7}-2}-\frac{5}{4+\sqrt{7}}\)
b, \(\frac{1}{\sqrt{3}+\sqrt{2}-\sqrt{5}}-\frac{1}{\sqrt{3}+\sqrt{2}+\sqrt{5}}\)
c, \(\frac{1}{\sqrt{3}}+\frac{1}{3\sqrt{2}}+\frac{1}{\sqrt{3}}\sqrt{\frac{5}{12}-\frac{1}{\sqrt{6}}}\)