Tính \(C=\frac{1}{2\sqrt{1}+1\sqrt{2}}+\frac{1}{3\sqrt{2}+2\sqrt{3}}+...+\frac{1}{2019\sqrt{2018}+2018\sqrt{2019}}\)
Rút gọn biểu thức:
\(a,\frac{1}{\sqrt{2}+\sqrt{2+\sqrt{3}}}+\frac{1}{\sqrt{2}-\sqrt{2-\sqrt{3}}}\)
\(b,\frac{1}{1+\sqrt{2}}+\frac{1}{\sqrt{2}+\sqrt{3}}+...+\frac{1}{\sqrt{2019}+\sqrt{2020}}\)
I : Rút gọn
\(A=\frac{1}{2\sqrt{1}+1\sqrt{2}}+\frac{1}{3\sqrt{2}+2\sqrt{3}}+...+\frac{1}{2019\sqrt{2020}+2020\sqrt{2019}}\)
help me !!!
Tính: \(B=\sqrt{1+\frac{1}{1^2}+\frac{1}{2^2}}+\sqrt{1+\frac{1}{2^2}+\frac{1}{3^2}}+....+\sqrt{1+\frac{1}{2018^2}+\frac{1}{2019^2}}\)
tính A = \(\sqrt{1+2018^2+\left(\frac{2018}{2019}\right)^2}+\frac{2018}{2019}\)
tính A=\(\sqrt{1+2018^2+\left(\frac{2018}{2019}\right)^2+\frac{2018}{2019}}\)
1)Cho tam giác ABC có AB=\(2\sqrt{2}\);AC=\(2\sqrt{3}\);và góc BAC =60 độ có diện tích bằng ?
2)Cho S=\(\frac{2020}{2\sqrt{1}+1\sqrt{2}}+\frac{2020}{3\sqrt{2}+2\sqrt{3}}+\frac{2020}{4\sqrt{3}+3\sqrt{4}}+...+\frac{2020}{2020\sqrt{2019}+2019\sqrt{2020}}\)
Tính S=?
=>giúp e vs các ac
\(\frac{1}{1\sqrt{1}}+\frac{1}{2\sqrt{2}}+...+\frac{1}{2019\sqrt{2019}}\) < \(2\sqrt{2}\)