Mathematics 9709 · AS & A Level · Series

Series — practice question

(i)[2]

Find the first three terms, written in ascending powers of $x$, in the expansion of $(1 - 2x)^5$.

(ii)[3]

If the coefficient of $x^2$ in the expansion of $(1 + ax + 2x^2)(1 - 2x)^5$ is $12$, determine the value of the constant $a$.

Worked solution & mark scheme

This 5-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Accurate expansion of $(1-2x)^5$ to obtain $1-10x+40x^2$.” …

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