1,2,3,...,99,100; 2,3,4,...,100,101; 4,5,6,...,101,102;...100,101,102,...,198,199;求下面数阵中所有数的和.

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1,2,3,...,99,100; 2,3,4,...,100,101; 4,5,6,...,101,102;...100,101,102,...,198,199;求下面数阵中所有数的和.

1,2,3,...,99,100; 2,3,4,...,100,101; 4,5,6,...,101,102;...100,101,102,...,198,199;求下面数阵中所有数的和.
1,2,3,...,99,100; 2,3,4,...,100,101; 4,5,6,...,101,102;...100,101,102,...,198,199;
求下面数阵中所有数的和.

1,2,3,...,99,100; 2,3,4,...,100,101; 4,5,6,...,101,102;...100,101,102,...,198,199;求下面数阵中所有数的和.
1+2+3+.+99+100=101×50=5050
100+101+.+198+199=5050+99×100= 14950
(5050+14950)×50=20000×50=1000000

第一行数字的和为a1=(1+100)100/2
第n行数字的和为an=(n+99+n)100/2=(2n+99)50
S(100)=a1+a2+.......+a100=50(99*100+202*50)=1000000
S(99)=a1+a2+.......+a99=50(99*99+100*99)=985050
你的题目抄的有点乱到底是 99行还是100行? 自己选上面的答案吧
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