比较下面两个积的大小.(请写出比较过程)A=1.23456×6.56789B=1.23457×6.56788
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比较下面两个积的大小.(请写出比较过程)A=1.23456×6.56789B=1.23457×6.56788
比较下面两个积的大小.(请写出比较过程)A=1.23456×6.56789B=1.23457×6.56788
比较下面两个积的大小.(请写出比较过程)A=1.23456×6.56789B=1.23457×6.56788
A=1.23456×6.56789=123456×656789 * 10^-10
B=1.23457×6.56788=123457×656788* 10^-10
有这样一个定律：两之和相同,两数越接近,两数积越大
123457+656788=123456+656789
656788-123457A
看不懂
A-B=1.23456×6.56789-1.23457×6.56788
=1.23456×(6.56788+0.00001)-(1.23456+0.00001)×6.56788
=1.23456×6.56788+1.23456×0.00001-1.23456×6.56788-0.00001×6.56788
=1.23456×0.00001-0.00001×6.56788
=0.00001(1.23456-6.56788)
=-0.00001×5.33332=-0.0000533332<0
所以A
A
=1.23456×6.56789
= (1.23457 - 0.00001) ×(6.56788 + 0.00001)
=1.23457 × 6.56788 + 1.23457×0.00001 - 6.56788 ×0.00001 - 0.00001×0.00001
=1.23457 × 6.56788 + 0.00001×(1.23457 - 6.56788...
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A
=1.23456×6.56789
= (1.23457 - 0.00001) ×(6.56788 + 0.00001)
=1.23457 × 6.56788 + 1.23457×0.00001 - 6.56788 ×0.00001 - 0.00001×0.00001
=1.23457 × 6.56788 + 0.00001×(1.23457 - 6.56788 - 0.00001)
=1.23457 × 6.56788 - 5.33332 × 0.00001
因为B = 1.23457 × 6.56788
所以A = B - 5.33332 × 0.00001
显然A 比 B大
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