Date | May 2013 | Marks available | 4 | Reference code | 13M.1.hl.TZ2.3 |
Level | HL only | Paper | 1 | Time zone | TZ2 |
Command term | Expand | Question number | 3 | Adapted from | N/A |
Question
Expand (2−3x)5 in ascending powers of x, simplifying coefficients.
Markscheme
clear attempt at binomial expansion for exponent 5 M1
25+5×24×(−3x)+5×42×23×(−3x)2+5×4×36×22×(−3x)3
+5×4×3×224×2×(−3x)4+(−3x)5 (A1)
Note: Only award M1 if binomial coefficients are seen.
=32−240x+720x2−1080x3+810x4−243x5 A2
Note: Award A1 for correct moduli of coefficients and powers. A1 for correct signs.
Total [4 marks]
Examiners report
Generally well done. The majority of candidates obtained a quintic with correct alternating signs. A few candidates made arithmetic errors. A small number of candidates multiplied out the linear expression, often correctly.