计算(-1x1⼀2)+(-1⼀2x1⼀3)+(-1⼀3x1⼀4)+....+(-1⼀2004x1⼀2005)=()(写过程)

2025-05-18 04:55:16
推荐回答(1个)
回答1:

=-(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