计算 (a-b)^2n - 2(b-a)^2n-1 - 2/3 (b-a)^2n - 1/2(a-b)^2n-1其中a=b-1 ,b为正整数.得数是-7/6 还是 1/6?

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计算 (a-b)^2n - 2(b-a)^2n-1 - 2/3 (b-a)^2n - 1/2(a-b)^2n-1其中a=b-1 ,b为正整数.得数是-7/6 还是 1/6?
计算 (a-b)^2n - 2(b-a)^2n-1 - 2/3 (b-a)^2n - 1/2(a-b)^2n-1
其中a=b-1 ,b为正整数.
得数是-7/6 还是 1/6?

计算 (a-b)^2n - 2(b-a)^2n-1 - 2/3 (b-a)^2n - 1/2(a-b)^2n-1其中a=b-1 ,b为正整数.得数是-7/6 还是 1/6?
∵a=b-1
∴a-b=-1
(a-b)^2n - 2(b-a)^(2n-1)- 2/3 (b-a)^2n - 1/2(a-b)^(2n-1)
=(a-b)^2n+2(a-b)^(2n-1)-2/3(a-b)^2n-1/2(a-b)^(2n-1)
=1/3(a-b)^2n+3/2(a-b)^(2n+1)
=1/3(-1)^2n+3/2(-1)^(2n+1)
=1/3-3/2
=2/6-9/6
=-7/6

a=b-1
a-b=-1
(a-b)^2n - 2(b-a)^2n-1 - 2/3 (b-a)^2n - 1/2(a-b)^2n-1
=(a-b)^2n + 2(a-b)^2n-1 - 2/3 (a-b)^2n - 1/2(a-b)^2n-1
=1/3(a-b)^2n+3/2(a-b)^2n-1
=1/3-3/2
=-7/6=(a-b)^2n + 2...

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a=b-1
a-b=-1
(a-b)^2n - 2(b-a)^2n-1 - 2/3 (b-a)^2n - 1/2(a-b)^2n-1
=(a-b)^2n + 2(a-b)^2n-1 - 2/3 (a-b)^2n - 1/2(a-b)^2n-1
=1/3(a-b)^2n+3/2(a-b)^2n-1
=1/3-3/2
=-7/6

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