A-Level Maths: D5-05 Geometric Sequences: A Sequences Problem

[@adamjsjsne3838]

How can you assume that the sequence is geometric as it could easily be arithmetic with a d=0.501

[@TLMaths]

But that's not the difference between u_3 and u_2 so it can't be arithmetic. You're multiplying each term by 1.5 to get to the next term, that is a geometric sequence.

[@puddleduck1405]

that is just the difference between the first 2 terms. The difference between the next two is 0.7515, and the difference keeps increasing, but if it was arithmetic, the d would be constant. In inductive definitions, if it multiples to get to the next term, it is always geometric, and if it adds it is always arithmetic