北师大版七年级上册数学书习题2.13答案
1习题2.13第1题答案
(1)-6,3
(2)-6/5,4
2习题2.13第2题答案
(1)72
=7×7
=49
(2)(-6)3
=(-6)×(-6)×(-6)
=-216
(3)(2/3)3
=2/3×2/3×2/3
=8/27
(4)-32
=-3×3
=-9
(5)-22/5
=-(2×2×2)/5
=-8/5
(6)-(-3/4)3
=[(- 3/4)×(-3/4)×(-3/4)]
=-(-27/64)
=27/64
3习题2.13第3题答案
一张纸对折1次是2页,对折2次是2×2页,对折3次是2×2×2页,对折4次是2×2×2×2页,…,对折n次是 页,即2n页
4习题2.13第4题答案
4或-4;可能,0的平方是0
5习题2.13第5题答案
(1)(-1)2n=1
(2)(-1)2n+1=-1