Tính tổng:
S=\(\sqrt{1+\frac{8.1^2-1}{1^2.3^2}}++\sqrt{1+\frac{8.2^2-1}{3^2.5^2}}++\sqrt{1+\frac{8.3^2-1}{5^2.7^2}}+...++\sqrt{1+\frac{8.1009^2-1}{2017^2.2019^2}}\)
Rút gọn biểu thức sau :
a)\(\frac{2}{\sqrt{7}-5}-\frac{2}{\sqrt{7}+5}\)
b)\(\frac{\sqrt{7}+\sqrt{5}}{\sqrt{7}-\sqrt{5}}+\frac{\sqrt{7}-\sqrt{5}}{\sqrt{7}+\sqrt{5}}\)
c)\(\left(\frac{\sqrt{14}-\sqrt{7}}{1-\sqrt{2}}+\frac{\sqrt{15}-\sqrt{5}}{1-\sqrt{3}}\right)\frac{1}{\sqrt{7}-\sqrt{5}}\)
d)\(\frac{3}{\sqrt{5}-2}+\frac{2}{\sqrt{5}+3}-\frac{1}{\sqrt{5}+4}\)
giúp mình với ạ
Thực hiện phép tính:
a)\(\frac{5}{a-\sqrt{11}}+\frac{1}{3\sqrt{7}}-\frac{6}{\sqrt{7}-2}-\frac{\sqrt{7}-5}{2}\)
b)\(\frac{\sqrt{5}-\sqrt{3}}{\sqrt{5}+\sqrt{3}}+\frac{\sqrt{5}+\sqrt{3}}{\sqrt{5}-\sqrt{3}}-\frac{\sqrt{5}+1}{\sqrt{5}-1}\)
c)\(\left(\frac{9-2\sqrt{14}}{\sqrt{7}-\sqrt{2}}\right)^2-\left(\frac{9+2\sqrt{14}}{\sqrt{7}-\sqrt{2}}\right)^2\)
Rút gọn biểu thức sau :
A = \(\frac{1}{4\sqrt{1}+1\sqrt{4}}+\frac{1}{7\sqrt{4}+4\sqrt{7}}+\frac{1}{10\sqrt{7}+7\sqrt{10}}...+\frac{1}{2007\sqrt{2004}+2004\sqrt{2007}}\)
1,Rút gọn:
a, \(\frac{1}{\sqrt{2}+1}+\frac{1}{\sqrt{3}+\sqrt{2}}+\frac{1}{\sqrt{4}+2}\)
b,\(\frac{1}{\sqrt{1}-\sqrt{2}}-\frac{1}{\sqrt{2}-\sqrt{3}}+\frac{1}{\sqrt{3}-\sqrt{4}}-\frac{1}{\sqrt{4}-\sqrt{5}}+\frac{1}{\sqrt{5}-\sqrt{6}}-\frac{1}{\sqrt{6}-\sqrt{7}}+\frac{1}{\sqrt{7}-\sqrt{8}}-\frac{1}{\sqrt{8}-\sqrt{9}}\)
1. thực hiện phép tính
a.\(\frac{3+\sqrt{7}}{3-\sqrt{7}}-\frac{3-\sqrt{7}}{3+\sqrt{7}}\)
b,\(\left(\frac{\sqrt{2}+\sqrt{5}}{\sqrt{2}-5}-\frac{\sqrt{2}-5}{\sqrt{2}+5}\right):\frac{\sqrt{2}}{23}\)
c,\(5\sqrt{\frac{1}{5}}+\frac{1}{2}\sqrt{20}+\sqrt{5}\)
d,\(\sqrt{\frac{1}{2}}+\sqrt{4,5}+12,5\)
e, \(\frac{1}{2}\sqrt{48}-2\sqrt{75}-\sqrt{54}+5\sqrt{1\frac{1}{3}}\)
Tính:
\(a)\frac{1}{\sqrt{7-\sqrt{24}}+1}+\frac{1}{\sqrt{7+\sqrt{24}}-1}\\ b)\frac{1}{1+\sqrt{5}}+\frac{1}{\sqrt{5}+\sqrt{9}}+...+\frac{1}{\sqrt{2014}+\sqrt{2015}}\)
tinnh D = \(\left(\frac{\sqrt{21}-\sqrt{7}}{\sqrt{3}-1}+\frac{\sqrt{10}-\sqrt{5}}{\sqrt{2}-1}\right):\frac{1}{\sqrt{7}-\sqrt{5}}\)
tính
\(\frac{10}{1+\sqrt{4}}+\frac{10}{\sqrt{4}+\sqrt{7}}+\frac{10}{\sqrt{7}+\sqrt{10}}+...+\frac{10}{\sqrt{97}+\sqrt{100}}\)
