Easy -1.2 This is a straightforward application of the binomial theorem requiring students to identify the correct term (r=3) and calculate using the binomial coefficient formula. It's a routine AS-level question with a simple substitution into a standard formula, making it easier than average but not trivial since students must correctly handle the fractional coefficient and powers.
Question 3:
3 | Expands at least one term
correctly.
PI
Other terms: (3x)4 + C (3x)2 2
4 2
1
+ C (3x) 3 + 4
4 3 �2�
1 1
Condone use of coefficients
�2� �2�
only. | 1.1a | M1 | C (3x)3
4 1
1
�2�
Coefficient = 54
Selects their x3 term
PI | 1.1a | M1
States correct coefficient. | 1.1b | A1
Total | 3
Q | Marking instructions | AO | Marks | Typical solution
Find the coefficient of the $x^3$ term in the expansion of $\left(3x + \frac{1}{2}\right)^4$
[3 marks]
\hfill \mbox{\textit{AQA AS Paper 1 2022 Q3 [3]}}