Date | November 2016 | Marks available | 2 | Reference code | 16N.1.sl.TZ0.3 |
Level | SL only | Paper | 1 | Time zone | TZ0 |
Command term | Write down | Question number | 3 | Adapted from | N/A |
Question
The values in the fourth row of Pascal’s triangle are shown in the following table.
Write down the values in the fifth row of Pascal’s triangle.
Hence or otherwise, find the term in \({x^3}\) in the expansion of \({(2x + 3)^5}\).
Markscheme
1, 5, 10, 10, 5, 1 A2 N2
[2 marks]
evidence of binomial expansion with binomial coefficient (M1)
eg\(\,\,\,\,\,\)\(\left( {\begin{array}{*{20}{c}} n \\ r \end{array}} \right){a^{n - r}}{b^r}\), selecting correct term, \({(2x)^5}{(3)^0} + 5{(2x)^4}{(3)^1} + 10{(2x)^3}{(3)^2} + \ldots \)
correct substitution into correct term (A1)(A1)(A1)
eg\(\,\,\,\,\,\)\(10{(2)^3}{(3)^2},{\text{ }}\left( {\begin{array}{*{20}{c}} 5 \\ 3 \end{array}} \right){(2x)^3}{(3)^2}\)
Note: Award A1 for each factor.
\(720{x^3}\) A1 N2
Notes: Do not award any marks if there is clear evidence of adding instead of multiplying.
Do not award final A1 for a final answer of 720, even if \(720{x^3}\) is seen previously.
[5 marks]