Question

1/1*2*3*4+1/2*3*4*5+....+1/2013*2014*2015*2016

Answer 1

A = \(\dfrac{1}{1.2.3.4}+\dfrac{1}{2.3.4.5}+...+\dfrac{1}{2013.2014.2015.2016}\)

3A =\(\dfrac{3}{1.2.3.4}+\dfrac{3}{2.3.4.5}+...+\dfrac{3}{2013.2014.2015.2016}\)

3A = \(\dfrac{1}{1.2.3}-\dfrac{1}{2.3.4}+\dfrac{1}{2.3.4}-\dfrac{1}{3.4.5}+...+\dfrac{1}{2013.2014.2015}-\dfrac{1}{2014.2015.2016}\)

3A = \(\dfrac{1}{1.2.3}-\dfrac{1}{2014.2015.2016}\)

3A = \(\dfrac{2014.2015.2016-6}{6.2014.2015.2016}\)

A=\(\dfrac{2014.2015.2016-6}{6.2014.2015.2016}:3\)

A=\(\dfrac{2014.2015.2016-6}{6.2014.2015.2016}.\dfrac{1}{3}\)

A=\(\dfrac{2014.2015.2016-6}{9.2014.2015.2016}\)

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