Question

递推数列的通项问题还是不太明白,该怎么解

Answer 1

1=a1/1=1

bn=b1+1/(1*2)+1/(2*3)+...+1/n(n-1)

=b1+1-1/2+1/2-1/3...+1/(n-1)-1/n

=2-1/n

=(2n-1)/n

an=nbn=2n-1