A subscription-based fitness app tracks the number of new premium users each month. In the first three months after a major update, the number of new premium users, in thousands, was recorded as:
3k−28,k,k+63k - 28, \quad k, \quad k + 63k−28,k,k+6
where kkk is a constant. Given that the number of new users joining each month is modeled as a geometric series,
show that k2−5k−84=0k^2 - 5k - 84 = 0k2−5k−84=0.
Predict the number of new premium users joining in the 6th month.
The total number of all premium users who have joined the app since the update is predicted to exceed 5 million for the first time in the NNNth month.
Calculate the value of NNN according to the model.
Practise Edexcel A Level Maths 3.4 Geometric Series with exam-style questions for A Level Maths. 27 questions, matched to the Edexcel A Level Maths (9MA0) specification and written in Paper 1, Paper 2 and Paper 3 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.