Question

关于数列求和问题an=2^n+1 bn=(an -1)/(an*a(n+1)) 求bn前n项的和an= 2^n +1 就

Answer 1

n=2^n/Z((2^n)+1)(2^(n+1)+1)

分开

也就是1/(2^n+1)-1/(2^(n+1)+1)

列bn=1/(2^1+1)-1/(2^2+1)+1/(2^2+1)-1/(2^3+1)+……+1/(2^n+1)-1/(2^(n+1)+1)

既然bn=(1/5-1/(2^(n+1)+1))