1+2加三一直加到2001的等差数列求和怎么算

1+2加三一直加到2001的等差数列求和怎么算

第1个回答  2018-04-05
1+2+3+...+2001
=(1+2001)X2001÷2
=2001X2002÷2
=2001X1001
=2001X1000+2001X1
=2001000+2001
=2003001本回答被提问者采纳
第2个回答  2018-04-05
解:依题意得
1+2+3+...+2001
=(1+2001)X2001÷2
=2001X2002÷2
=2001X1001
=2001X(1000+1)
=2001X1000+2001X1
=2001000+2001
=2003001