O-LevelAdditional MathematicsSeries4037/22 · Oct/Nov 2021 · Q28 Marks

Expand (2-3x)⁴, evaluating all of the coefficients.

(a)Expand (2-3x)⁴, evaluating all of the coefficients.[4]
(b)The sum of the first three terms in ascending powers of x in the expansion of (2-3x)⁴(1 + (a/x)) is (32/x)+b+cx, where a, b and c are integers. Find the values of each of a, b and c.[4]

Mark scheme

Marking points from the official mark scheme (Oct/Nov 2021). The mark or mark type is shown in brackets.

[B4] Mark final answer for B4
[B3] for any 4 correct simplified terms in a sum or for all 5 simplified terms listed but not summed or for a correct simplified expansion that is not their final answer or
[B2] for any 3 correct simplified terms in a sum or for 4 correct simplified terms listed but not summed or
[B1] for any 2 correct simplified terms in a sum or for 3 correct simplified terms listed but not summed or
[M1] for correct unsimplified expansion 2⁴ + 4×2³ (-3x) + 6×2² (-3x)² + 4×2(-3x)³ + (-3x)⁴
[B1] FT Expansion using their (a)
[B1] FT their 16a/x
[B1]
[B1]

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About this question

Topic

Series, O-Level Additional Mathematics (syllabus 4037). Structured question, 8 marks.

Source

O-Level Additional Mathematics, Oct/Nov 2021 Paper 2 Variant 2, question 2.

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