Date | May 2009 | Marks available | 1 | Reference code | 09M.1.sl.TZ2.3 |
Level | SL only | Paper | 1 | Time zone | TZ2 |
Command term | Write down | Question number | 3 | Adapted from | N/A |
Question
The fifth term in the expansion of the binomial (a+b)n is given by (104)p6(2q)4 .
Write down the value of n.
[1]
a.
Write down a and b, in terms of p and/or q.
[2]
b.
Write down an expression for the sixth term in the expansion.
[3]
c.
Markscheme
n=10 A1 N1
[1 mark]
a.
a=p , b=2q (or a=2q , b=p ) A1A1 N1N1
[2 marks]
b.
(105)p5(2q)5 A1A1A1 N3
[3 marks]
c.
Examiners report
[N/A]
a.
[N/A]
b.
The most common error was in (c) where many candidates interpreted the "sixth" term as using (106) , with accompanying powers of 4 and 6 in the expression.
c.