问题 填空题
已知12+22+32+…+n2=
1
6
n(n+1)(2n+1),则22+42+62+…+1002=______.
答案

∵12+22+32+…+n2=

1
6
n(n+1)(2n+1),

∴12+22+32+…+1002=22+42+62+…+1002+(12+32+52+…+992

1
6
×100×(100+1)(2×100+1)=338350;

又∵22+42+62+…+1002-(12+32+52+…+992

=(22-12)+(42-32)+(62-52)+…+(1002-992

=(2+1)(2-1)+(4-3)(4+3)+(6+5)(6-5)+…+(100+99)(100-99)

=(2+1)+(4+3)+(6+5)+…+(100+99)

=5050;

∴22+42+62+…+1002=

338350+5050
2
=171700.

故答案为:171700.

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