解这道英文数学题目find the consecutive number whose cubes(i)differ by 37 (ii)add up to 35
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解这道英文数学题目find the consecutive number whose cubes(i)differ by 37 (ii)add up to 35
解这道英文数学题目
find the consecutive number whose cubes(i)differ by 37 (ii)add up to 35
解这道英文数学题目find the consecutive number whose cubes(i)differ by 37 (ii)add up to 35
设较小的数是n,
i) 那么:(n+1)^3-n^3=37,
(n+1)^3-n^3=(n+1-n)[(n+1)^2+n(n+1)+n^2]=3n^2+3n+1=37
n^2+n-12=0,(n+4)(n-3)=0,n=-4 或3
所以可以是-4,-3 或3,4.
2)(n+1)^3+n^3=35
(n+1)^3+n^3=2n^3+3n^2+3n+1=35
2n^3+3n^2+3n-34=0
2n^3+3n^2+3n-34=(2n^3-8n^2+8n)+(11n^2-5n-34)
=2n(n-2)^2+(11n+17)(n-2)
=(n-2)(2n^2-4n+11n+17)
=(n-2)(2n^2+7n+17)=0
n=2,(2n^2+7n+17=0无解)
所以是2和3.
(n+1)^3-n3=37 3n2+3n-36=0 n2+n=12 n(n+1)=12 所以数字是3 4
(n+1)3+n3=35 解的n=2 是 2 3
求出两个连续的整数 使它们的立方 1。相差37 2。加起来等于35
设小的数为n 大的数就是n+1
(n+1)^3-n^3=37
解出n=3或者-4
所以这两个数是3和4 或者 -4,-3
同理(n+1)^3+n^3=35
解出n=3
所以这两个数是2和3
1.3 4
2.2 3