a(2n-1)+a(2n+1)=2a(n+n-1)+0=2a(2n-1),
a(2n+1)=a(2n-1)=...=a(1)=0.
a(2n-1)=0.
a[2(n+1)-1] + a(2n+1) = 2a(n+1 + n-1) + 2(n+1-n)^2,
a(2n+1) + a(2n+1) = 0 = 2a(2n) + 2,
a(2n)=-1, 與a(2)=2矛盾哈.
題目有問題吧...題目就是這樣的?。?！我也不會(huì)做若不顧問題的話,解法如下:m=n+1,a[2(n+1)-1] + a(2n+1)=2a(n+1+n-1)+2(n+1-n)^2,2a(2n+1)=2a(2n) + 2,a(2n+1)=a(2n)+1,c(2n)=[a(2n+1)-a(2n)]q^(2n-1) = q^(2n-1),m=n,a(2n-1)+a(2n+1)=2a(n+n-1)+0=2a(2n-1),a(2n+1)=a(2n-1)a(2n-1)=a(2n+1)=a(2n)+1,c(2n-1)=[a(2n)-a(2n-1)]q^(2n-2)=-q^(2n-2).c(2n-1)+c(2n)=q^(2n-1)-q^(2n-2)=(q-1)q^(2n-2)=(q-1)(q^2)^(n-1)若q^2=1,s(2n)=[c(1)+c(2)]+...+[c(2n-1)+c(2n)]=[q-1] + [q-1]q^2 + ... + (q-1)(q^2)^(n-1)=(q-1)ns(2n-1)=s(2n)-c(2n)=(q-1)n-q^(2n-1).若q^2不等于1,s(2n)=[c(1)+c(2)]+...+[c(2n-1)+c(2n)]=[q-1] + [q-1]q^2 + ... + (q-1)(q^2)^(n-1)=(q-1)[(q^2)^n-1]/(q^2-1)=[q^(2n)-1]/(q+1)s(2n-1)=s(2n)-c(2n)=[q^(2n)-1]/(q+1)-q^(2n-1).