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?

来源:学生作业帮助网 编辑:作业帮 时间:2024/05/11 18:16:56
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?
x){nuHMz3(OAWH#I7Q5`@P1Di';&&U$=ٱϦny6u}ӁԳu^d5$Sl1m9]V˱3D(6FR&bI!#}3]K}36yvАsa@0M(ڵaڡصc iA°OOOWxټƩO4 ӠgSغI`{}

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...

全部展开

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

收起