Date | November 2013 | Marks available | 5 | Reference code | 13N.1.hl.TZ0.1 |
Level | HL only | Paper | 1 | Time zone | TZ0 |
Command term | Find | Question number | 1 | Adapted from | N/A |
Question
The cubic polynomial \(3{x^3} + p{x^2} + qx - 2\) has a factor \((x + 2)\) and leaves a remainder 4 when divided by \((x + 1)\). Find the value of p and the value of q.
Markscheme
\(f( - 2) = 0{\text{ }}( \Rightarrow - 24 + 4p - 2q - 2 = 0)\) M1
\(f( - 1) = 4{\text{ }}( \Rightarrow - 3 + p - q - 2 = 4)\) M1
Note: In each case award the M marks if correct substitution attempted and right-hand side correct.
attempt to solve simultaneously \((2p - q = 13,{\text{ }}p - q = 9)\) M1
\(p = 4\) A1
\(q = - 5\) A1
[5 marks]
Examiners report
Many candidates scored full marks on what was thought to be an easy first question. However, a number of candidates wrote down two correct equations but proceeded to make algebraic errors and thus found incorrect values for p and q. A small number also attempted to answer this question using long division, but fully correct answers using this technique were rarely seen.