SPS SPS FM 2022 February — Question 8 7 marks

Exam BoardSPS
ModuleSPS FM (SPS FM)
Year2022
SessionFebruary
Marks7
TopicGeneralised Binomial Theorem
TypeProduct with linear term
DifficultyModerate -0.3 Part (i) is a standard binomial expansion with negative index requiring straightforward application of the formula. Part (ii) requires multiplying two expansions and collecting terms, which is routine but involves more algebraic manipulation than a basic recall question. This is slightly easier than average A-level difficulty as it follows a predictable pattern with no conceptual challenges.
Spec1.04c Extend binomial expansion: rational n, |x|<11.04d Binomial expansion validity: convergence conditions

  1. Expand \((1 - 3x)^{-2}\) in ascending powers of \(x\), up to and including the term in \(x^2\). [3]
  2. Find the coefficient of \(x^2\) in the expansion of \(\frac{(1 + 2x)^2}{(1 - 3x)^2}\) in ascending powers of \(x\). [4]

\begin{enumerate}[label=(\roman*)]
\item Expand $(1 - 3x)^{-2}$ in ascending powers of $x$, up to and including the term in $x^2$. [3]
\item Find the coefficient of $x^2$ in the expansion of $\frac{(1 + 2x)^2}{(1 - 3x)^2}$ in ascending powers of $x$. [4]
\end{enumerate}

\hfill \mbox{\textit{SPS SPS FM 2022 Q8 [7]}}