s=i+2i^2+3i^3+……+2006i^2006+2007i^2007is=-1-2i-3i^2-.-2007i^2006s+is=-1-i-i^2-.-i^2006+2007i^2007=2007i^2007-(1-i^2007)/(1-i)(1+i)s=(2007i^2007-2007i^2008-1+i^2007)/(1-i)s=(2008i^2007-2008)/2=1004i-...