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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