Given geometric sequence tn find t6 and S∞ if t2 = 243 and t5=9

Answer 1

the fact that S∞ exists means that | r | < 1
... two terms that are three apart (t2 and t5) are both positive, so r is positive

243 r^3 = 9 ... r = ?

find r and t1 and plug them into the sum equation