Past Papers’ Solutions | Cambridge International Examinations (CIE) | AS & A level | Mathematics 9709 | Pure Mathematics 1 (P1-9709/01) | Year 2015 | May-Jun | (P1-9709/11) | Q#3
Question
i. Find the first three terms, in ascending powers of , in the expansion of
a.
b.
ii. Hence find the coefficient of in the expansion of
.
Solution
i.
a)
Expression for the Binomial expansion of is:
First we rewrite the given equation in the standard form;
In the given case:
Hence;
b)
Expression for the Binomial expansion of is:
In the given case:
Hence;
ii.
To find the coefficient of in the expansion of
.
From (i) we have;
Therefore;
Since we are interested only in terms with
Hence coefficient of is 3.
Comments