# Past Papers’ Solutions | Cambridge International Examinations (CIE) | AS & A level | Mathematics 9709 | Pure Mathematics 1 (P1-9709/01) | Year 2013 | Oct-Nov | (P1-9709/11) | Q#1

Question

i.
Find the first three terms in the expansion of  in ascending powers of .

ii.
In the expansion of  , the coefficient of  is zero, find the value of .

Solution

i.

Expression for the Binomial expansion of  is:

In the given case:

Hence;

ii.

To find the value of  in the expansion of

First we know from (i) that

Therefore:

Since coefficient of  is zero.