两个等差数列an,bn,a1+a2+a3+...an/b1+b2+b3+...bn=7n+2/n+3,则a5/b5=?

两个等差数列an,bn,a1+a2+a3+...an/b1+b2+b3+...bn=7n+2/n+3,则a5/b5=?
两个等差数列an,bn,a1+a2+a3+...an/b1+b2+b3+...bn=7n+2/n+3,则a5/b5=?

两个等差数列an,bn,a1+a2+a3+...an/b1+b2+b3+...bn=7n+2/n+3,则a5/b5=?
Sn=n*(a1+an)/2
Tn=n*(b1+bn)/2
a5=(a1+a9)/2
b5=(b1+b9)/2
所以
a5/b5=S9/T9=(7*9+2)/(9+3)=65/12