Question

等差数列{an} {bn}前n项和为An Bn,An/Bn=(7n+2)/(4n+27),求an/bn

Answer 1

因为等差数列{an} {bn}前n项和为An,Bn

所以an/bn=A2n-1/B2n-1

又An/Bn=(7n+2)/(4n+27)

所以A2n-1/B2n-1=[7*(2n-1)+2]/[4* (2n-1)+27]

所以an/bn=(14n-5)/(8n+23)