计算(-1x1/2)+(-1/2x1/3)+(-1/3x1/4)+.+(-1/2004x1/2005)=()(写过程)
问题描述:
计算(-1x1/2)+(-1/2x1/3)+(-1/3x1/4)+.+(-1/2004x1/2005)=()(写过程)
答
=-(1/1*2+1/2*3+……+1/2004*2005)
=-(1-1/2+1/2-1/3+1/3-1/4+……+1/2004-1/2005)
=-(1-1/2005)
=-2004/2005