If a1=a,an=ba_1=a, a_n=ba1=a,an=b, find an+1a_{n+1}an+1.
b+(b−a)/(n−1)b + (b-a)/(n-1)b+(b−a)/(n−1)
b+(b−a)/nb + (b-a)/nb+(b−a)/n
2b−a2b-a2b−a
None