(i)[4]
Find the exact value for $a$.
(ii)[3]
With this value of $a$, obtain the expansion up to and including the term in $x^2$, with coefficients simplified.
Mathematics 9709 · AS & A Level · Differentiation
Differentiation — practice question
In the expansion of $(1 + ax)^{-2}$, where $a$ is a positive constant, written as a power series in increasing powers of $x$, the coefficients of $x$ and $x^3$ are the same.