Question

What are the values of r and a1 for 1/4(2)k-1

Answer 1

c

Explanation:

Answer 2

Given:

`\sum_(k=1)^(6)(1)/(4)(2)^(k-1)`

To find:

The values of r and
`a_1`.

Solution:

We have,

`\sum_(k=1)^(6)(1)/(4)(2)^(k-1)`

Here,

`a_k=(1)/(4)(2)^(k-1)` ...(i)

We know that, kth term of a GP is

`a_k=a_1(r)^(k-1)` ...(ii)

From (i) and (ii), we get

`a_1=(1)/(4)` and
`r=2`

Therefore, the correct option is C.