Past Papers’ Solutions | Cambridge International Examinations (CIE) | AS & A level | Mathematics 9709 | Pure Mathematics 1 (P1-9709/01) | Year 2018 | May-Jun | (P1-9709/11) | Q#1

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Question

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

                  ii.       Given that the coefficient of  in the expansion of is 12, find the value of the constant a.

Solution


i.
 

Expression for the Binomial expansion of  is:

First rewrite the given expression in standard form.

In the given case:

Hence;

 

 


ii.
 

To find the term with   in the expansion of

From (i) we have;

Therefore;

 

 

 

 

 

We are interested only in coefficient of which is equal to 12.,

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