2×2×2+4×4×4+6×6×6+…+98×98×98+100×100×100 简便计算~

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2×2×2+4×4×4+6×6×6+…+98×98×98+100×100×100 简便计算~
2×2×2+4×4×4+6×6×6+…+98×98×98+100×100×100 简便计算~

2×2×2+4×4×4+6×6×6+…+98×98×98+100×100×100 简便计算~
设2×2×2为a
原式=a+8a+27a+…
=1³a+2³a+3³a+...+49³a+50³a
=(1+2+3+...+50)²a
=1275²a
=1625625×(2×2×2)
=13005000
=1³a+2³a+3³a+...+49³a+50³a
=(1+2+3+...+50)²a推倒如下

1*1*1+2*2*2
=9
=3*3
=1×1×1+2×2×2+3×3×3
=36
=6*6
=(1+2+3)×(1+2+3)
所以可以的到结论如下:
1×1×*1+2×2×2+3×3×3+...+x×x×x
=(1+2+3+...+x)×(1+2+3+...x)

(2+4+6+...+98+100)*3

(2+4+6......+98+100)的三次幂

2*2*2+4*4*4+6*6*6+···+98*98*98+100*100*100
=8*(1^3+2^3+3^3+...+50^3)
=8*(1+8+27+...+50^3)
=8*[(50+1)*50/2]^2
=8*1/4*2601^2
=2*6765201
=13530402
注:1^3+2^3+3^3+。。。+n^3=[(n+1...

全部展开

2*2*2+4*4*4+6*6*6+···+98*98*98+100*100*100
=8*(1^3+2^3+3^3+...+50^3)
=8*(1+8+27+...+50^3)
=8*[(50+1)*50/2]^2
=8*1/4*2601^2
=2*6765201
=13530402
注:1^3+2^3+3^3+。。。+n^3=[(n+1)n/2]^2

收起

2³+4³+6³……+98³+100³
=8×(1³+2³+3³+...+50³)
=8×(51×50÷2)²
=8×1625625
=13005000