数学题,在下面,速度!都要简便计算!谢谢
(1)9999×2222+3333×3334
(2)1+1/2+2/2+1/3+2/3+3/3+1/4+2/4+3/4+4/4+……+1/100+2/100+……+100/100
(3)1/2+1/4+1/8+1/16+1/32+1/64
(4)1/1×2×3+1/2×3×4+1/3×4×5+……+1/98×99×100
人气:195 ℃ 时间:2020-04-28 15:55:49
解答
(1)9999×2222+3333×3334=3333x2222x3+3333x3334=3333x(6666+3334)=3333x10000=33330000(2)1+1/2+2/2+1/3+2/3+3/3+1/4+2/4+3/4+4/4+……+1/100+2/100+……+100/100因为1+2+3+……+n-1+n=n(n+1)/2 所以1/n+2/n+3...
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