\(x:\left(\dfrac{-1}{2}\right)^3=\dfrac{-1}{2}\)

\(x=\dfrac{-1}{2}.\left(\dfrac{-1}{2}\right)^3\)

\(x=\dfrac{-1}{2}.\dfrac{-3}{6}\)

\(x=\dfrac{3}{12}\)

\(x=\dfrac{1}{4}\)

Đặt \(A=\dfrac{4}{2.4}+\dfrac{4}{4.6}+\dfrac{4}{6.8}+...+\dfrac{4}{2008.2010}\)

\(A=4.\dfrac{1}{2}.\left(\dfrac{2}{2.4}+\dfrac{2}{4.6}+\dfrac{2}{6.8}+...+\dfrac{2}{2008.2010}\right)\)

\(A=2.\left(\dfrac{1}{2}-\dfrac{1}{4}+\dfrac{1}{4}-\dfrac{1}{6}+\dfrac{1}{6}-\dfrac{1}{8}+...+\dfrac{1}{2008}-\dfrac{1}{2010}\right)\)

\(A=2.\left(\dfrac{1}{2}-\dfrac{1}{2010}\right)\)

\(A=1-\dfrac{2}{2010}\)

\(A=1-\dfrac{1}{1005}\)

mik nè