Rút gọn \(\frac{1-\sqrt{2}+\sqrt{3}}{1+\sqrt{2}+\sqrt{3}}+\frac{1-\sqrt{4}+\sqrt{5}}{1+\sqrt{4}+\sqrt{5}}+...+\frac{1-\sqrt{2018}+\sqrt{2019}}{1+\sqrt{2018}+\sqrt{2019}}\)
Rút gọn biểu thức: A= \(\frac{\sqrt{x-2017-2\sqrt{x-2018}}}{\sqrt{x-2018}-1}\)Với x > 2019
So sánh \(\sqrt{2019^2-1}-\sqrt{2018^2-1}\) và \(\frac{2.2018}{\sqrt{2019^2-1}+\sqrt{2018^2-1}}\)
tim x , y thoa man \(y=\sqrt{\frac{2018x+2019}{2017x-2018}}+\sqrt{\frac{2018x+2019}{2018-2017x}}+2018\)
Tính:
A= \(\frac{1}{2\sqrt{1}+1\sqrt{2}}\)+ \(\frac{1}{3\sqrt{2}+2\sqrt{3}}\)+....+ \(\frac{1}{2019\sqrt{2018}+2018\sqrt{2019}}\)
tính \(\sqrt{1+2018^2+\frac{2018}{2019}^2}+\frac{2018}{2019}\)
Tính \(\sqrt{1+2018^2+\frac{2018^2}{2019^2}}+\frac{2018}{2019}\)
Tính:
\(\sqrt{1+2018^2+\frac{2018^2}{2019^2}}+\frac{2018}{2019}\)
tính
\(\frac{1}{\sqrt{2}-\sqrt{3}}-\frac{1}{\sqrt{3}-\sqrt{4}}+\frac{1}{\sqrt{4}-\sqrt{5}}+...+\frac{1}{\sqrt{2018}-\sqrt{2019}}\)