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

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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+……

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
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

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
(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/n+……+n-1/n+n/n=n(n+1)/2n=(n+1)2
所以楼主所问问题为:
(1+1)/2+(2+1)/2+(3+1)/2+……+(n+1)/2
=(1+2+3+……+n)/2+n*(1/2)
=(n(n+1)/2)/2+n/2
=n*(n+1)/4+n/2
=n*n+3n/4
(3)1/2+1/4+1/8+1/16+1/32+1/64
=(32+16+8+4+2+1)/64
=63/64
(4)1/1×2×3+1/2×3×4+1/3×4×5+……+1/98×99×100
=1/2[(1/1×2-1/2×3)+(1/2×3-1/3×4)+……(1/98×99-1/99×100)
=1/2(1-1/9900)
=9899/19800