(-1乘1/2)+(-1/2乘1/3)+.+(-1/2007乘1/2008)等于

问题描述:

(-1乘1/2)+(-1/2乘1/3)+.+(-1/2007乘1/2008)等于

原式=(1/2-1)+(1/3-1/2)+……+(1/2008-1/2007)
=1/2008-1
=-2007/2008