# Past Papers’ Solutions | Edexcel | AS & A level | Mathematics | Core Mathematics 1 (C1-6663/01) | Year 2016 | June | Q#6

Question

A sequence  is defined by

,

Where  is a constant.

a)   Write down expressions for  and  in terms of k.

Find,

b)   in terms of k, giving your answer in its simplest form.

c)   .

Solution

a)

We are given that sequence  is defined by

We are required to find  and .

We can utilize the given expression for general terms beyond first term as;

Similarly;

b)

We are required to find;

We can substitute given  and found  from (a);

c)

We are required to find;