等比数列和的公式a1(1-q^n)/(1-q)
a=2005+2004*2005+2004*2005^2+……+2004*2005^2004
=2005+2004*(2005+2005^2+……+2005^2004)
=2005+2004*(2005(1-2005^2004)/(1-2005))
=2005+2005^2005-2005
=2005^2005
=
等比数列和的公式a1(1-q^n)/(1-q)
a=2005+2004*2005+2004*2005^2+……+2004*2005^2004
=2005+2004*(2005+2005^2+……+2005^2004)
=2005+2004*(2005(1-2005^2004)/(1-2005))
=2005+2005^2005-2005
=2005^2005
=