1MA0 Higher March 2013 Paper 1 Q5
5 Here are the first 5 terms of an arithmetic sequence.
3 9 15 21 27
(a) Find an expression, in terms of \(n\), for the \(n\)th term of this sequence. (2)
Ben says that 150 is in the sequence.
(b) Is Ben right?
You must explain your answer. (1)
You must explain your answer. (1)
| Answer | Mark | Notes |
|---|---|---|
| \(6n - 3\) | 2 | M1 for attempt to establish linear expression in \(n\) with coefficient of 6 e.g. \(6n + k\) where \(k\) is an integer (accept \(n = 6n - 3\) for one mark) A1 cao |
| Answer | Mark | Notes |
|---|---|---|
| No + Reason | 1 | C1 ft from their answer to part (a) for decision and explanation eg “stating no and because all the terms in the sequence are odd and 150 is even” or “no and ‘\(6n - 3\)’ = 150, \(n = 153/6\) ... so \(n\) is not an integer” or Continuing the sequence to show terms 147 and 153 and state “no as 150 is not in the sequence” oe |