Ta có:\(C=\left(\dfrac{1}{2}-1\right)\times\left(\dfrac{1}{3}-1\right)\times\left(\dfrac{1}{4}-1\right)\times...\times\left(\dfrac{1}{2006}-1\right)\times\left(\dfrac{1}{2007}-1\right)\)
\(=\dfrac{-1}{2}\times\dfrac{-2}{3}\times\dfrac{-3}{4}\times...\times\dfrac{-2005}{2006}\times\dfrac{-2006}{2007}\)
\(=\dfrac{1}{2007}\)
Ta có: \(C=\left(\dfrac{1}{2}-1\right)\left(\dfrac{1}{3}-1\right)\cdot...\cdot\left(\dfrac{1}{2006}-1\right)\left(\dfrac{1}{2007}-1\right)\)
\(=\dfrac{-1}{2}\cdot\dfrac{-2}{3}\cdot\dfrac{-3}{4}\cdot...\cdot\dfrac{-2005}{2006}\cdot\dfrac{-2006}{2007}\)
\(=\dfrac{1}{2007}\)
