1x2 / 2005 + 2x3 / 2005 + 3x4 / 2005 + 4x5 / 2005 + 10 2005 out of 10 2004x2005 = ()
=2005x(1/1x2+1/2x3+.1/2004x2005)
=2005x(1/1-1/2+1/2-1/3+.1/2004-1/2005)
=2005x(1-1/2005)
=2005x2004/2005
=2004
RELATED INFORMATIONS
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