计算:36+49+64+81+…+400?亲们 -
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![计算:36+49+64+81+…+400?亲们 -](/uploads/image/z/442575-63-5.jpg?t=%E8%AE%A1%E7%AE%97%EF%BC%9A36%2B49%2B64%2B81%2B%E2%80%A6%2B400%3F%E4%BA%B2%E4%BB%AC+-)
计算:36+49+64+81+…+400?亲们 -
计算:36+49+64+81+…+400?
亲们 -
计算:36+49+64+81+…+400?亲们 -
1^2+2^2+3^2+...n^2=n(n+1)(2n+1)/6
36+49+64+81+…+400
=6²+7²+…20²
=1²+2²+...+5²+6²+…20²-(1²+2²+...+5²)
=(20×21×41)÷6-(5×6×11)÷6
=2815
数与数之间相差13,15,17。。。。。。37
36+49+64+........394+400=3103