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北师大版七年级上册数学书习题2.14答案

时间:2016-04-21 来源:书通网 共计3题

习题2.14第1题答案

(1)-34

=-(3×3×3×3)

=-81

(2)-(-3)3

=-[(-3)×(-3)×(-3)]

=27

(3)-(-2/3)4

=-(2/3×2/3×2/3×2/3)

=- 16/81

(4)(4/5)2

=4/5×4/5

=16/25

(5)-3/22

=-3/(2×2)

=-3/4

(6)-(-2/5)3

=-[(-2/5)×(-2/5)×(-2/5)]

=8/125

习题2.14第2题答案

(1/2)7=1/128(m)

因此第7次后剩下的木棒有1/128m长

习题2.14第3题答案

(1)1/2×1/2×1/2×1/2×1/2×1/2=[(1/2)]6=1/64

(2)1/2+1/4+1/8+…+1/26 =1-1/64=63/64

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