1, 7, 13, 19, 25, ...
- (a)1, 7, 13, 19, 25, ...
- (a)(i)Find an expression, in terms of n, for the nth term of this sequence.[2]
- (a)(ii)Explain why 251 is not a term in this sequence.[1]
- (b)Here is another sequence. 5, 8, 13, 20, 29, ... The pth term of this sequence is p² + 4. Write down an expression, in terms of p, for the pth term of these sequences.
- (b)(i)2, 1, 6, 13, 22, ...[1]
- (b)(ii)7, 12, 19, 28, 39, ...[1]
- (c)The diagrams below show the first three patterns in a sequence. The patterns are made from short diagonal lines.
- (c)(i)Draw Pattern 4 on the dotty grid below.[1]
- (c)(ii)Complete the table below for the number of short lines in Patterns 4 and 5. Pattern 1 2 3 4 5 Number of short lines 4 10 18[2]
- (c)(iii)Find an expression, in terms of t, for the number of short lines in Pattern t.[2]
This question uses a diagram from the original paper, which isn't shown here. Open the full paper from the past papers archive to see it.
Mark scheme
Marking points from the official mark scheme (May/June 2018). The mark or mark type is shown in brackets.
- [2] 6n - 5 oe
- [2] M1 for 6n + k oe with k≠ 0
- [1] 256 is not exactly divisible by 6 or 247 in sequence and next one is 253 oe
- [1] p² - 3 oe
- [1] p² + 2p + 4 oe
- [1] Correct drawing
- [2] 28, 40
- [2] B1 for one correct
- [2] t² + 3t oe
- [2] B1 for t² + ...
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