tính:\(\frac{1}{\sqrt{1}-\sqrt{2}}-\frac{1}{\sqrt{2}-\sqrt{3}}+\frac{1}{\sqrt{3}-\sqrt{4}}-\frac{1}{\sqrt{4}-\sqrt{5}}+\frac{1}{\sqrt{5}-\sqrt{6}}-\frac{1}{\sqrt{6}-\sqrt{7}}+\frac{1}{\sqrt{7}-\sqrt{8}}-\frac{1}{\sqrt{8}-\sqrt{9}}\)
Tính :
a ) \(S=\frac{1}{\sqrt{1}\sqrt{3}}+\frac{1}{\sqrt{3}+\sqrt{5}}+\frac{1}{\sqrt{5}+\sqrt{7}}+.....+\)\(\frac{1}{\sqrt{2017}+\sqrt{2019}}\)
b ) \(S=\frac{1}{\sqrt{2}+\sqrt{4}}+\frac{1}{\sqrt{4}+\sqrt{6}}+....+\frac{1}{\sqrt{100}+\sqrt{102}}\)
c ) \(S=\frac{1}{\sqrt{1}+\sqrt{2}}+\frac{1}{\sqrt{2}+\sqrt{3}}+.....+\frac{1}{\sqrt{100}+\sqrt{101}}\)
d ) \(S=\frac{1}{\sqrt{3}+\sqrt{6}}+\frac{1}{\sqrt{6}+\sqrt{9}}+\frac{1}{\sqrt{9}+\sqrt{12}}+....+\frac{1}{\sqrt{2016}+\sqrt{2019}}\)
\(A=\left(\sqrt{3}+1\right)^2+\frac{5}{4}\sqrt{48}-\frac{2}{\sqrt{3+1}}\)
\(B=\frac{4}{3-\sqrt{5}}-\frac{3}{\sqrt{5}+\sqrt{2}}-\frac{1}{\sqrt{2}-1}\)
\(C=\sqrt{4-2\sqrt{3}}-\sqrt{7+4\sqrt{3}}\)
Rút gọn
Giúp mình với mình cần gấp
Rút gọn:
\(A=\left(\frac{2+\sqrt{x}}{x-5\sqrt{x}+6}-\frac{\sqrt{x}+3}{2-\sqrt{x}}-\frac{\sqrt{x}+2}{\sqrt{x}-3}\right):\left(2-\frac{\sqrt{x}}{1+\sqrt{x}}\right)\)
\(P=\frac{2\sqrt{X}-9}{x-5\sqrt{X+6}}-\frac{\sqrt{X}+3}{\sqrt{X}-2}-\frac{2\sqrt{X}+1}{3-\sqrt{X}}\)
Rút gọn P
Tính P nếu x = 6 - \(2\sqrt{5}\)
Tìm x để B=3A,biếtA=\(\left(\frac{5+2\sqrt{6}}{\sqrt{3}+\sqrt{2}}+\frac{5-2\sqrt{6}}{\sqrt{3}-\sqrt{2}}\right)\) /\(\left(\frac{1}{2\sqrt{5}+3\sqrt{2}}-\frac{1}{2\sqrt{5}-3\sqrt{2}}\right)\)
B=\(\frac{2x^4-x^3+2x^2+x-4}{2x^3-x^2-2x+1}\)
Cho \(A=\frac{x\sqrt{x}+5\sqrt{x}-12}{x-\sqrt{x}-6}-\frac{2\sqrt{x}-6}{\sqrt{x}+2}+\frac{\sqrt{x}+3}{3-\sqrt{x}}.\)
1.Rút gọn A
a/\(\frac{5-2\sqrt{5}}{\sqrt{5}}+\frac{20}{5+\sqrt{5}}\)
b/\(\frac{3+2\sqrt{3}}{\sqrt{3}}+\frac{2+\sqrt{2}}{\sqrt{2}}-\left(\sqrt{3}+\sqrt{2}\right)\)
\(y=1-\frac{\sqrt{x}}{\sqrt{x+}1}:\frac{2+\sqrt{x}}{x-5\sqrt{x+6}}+\frac{3+\sqrt{x}}{\sqrt{x-2}}-\frac{2+\sqrt{x}}{\sqrt{x-3}}\)