Past Papers’ Solutions | Cambridge International Examinations (CIE) | AS & A level | Mathematics 9709 | Pure Mathematics 1 (P1-9709/01) | Year 2013 | May-Jun | (P1-9709/11) | Q#2
Question
i. In the expression ,
is non-zero constant. Find the first 3 terms in the expansion
of , in ascending powers of
.
ii. It is given that the coefficient of in the expansion of
is zero. Find the value of
.
Solution
i.
First rewrite the given expression in standard form.
Expression for the Binomial expansion of is:
In the given case:
Hence;
ii.
First we know from (i) that
Therefore:
Since the coefficient of variable is zero.
Therefore:
&
Since is a non-zero constant. We only consider:
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