Question

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

Answer 1

Answer:

c

Step-by-step explanation:

Answer 2

Given:

$\sum_{k=1}^{6}\dfrac{1}{4}(2)^{k-1}$

To find:

The values of r and $a_1$.

Solution:

We have,

$\sum_{k=1}^{6}\dfrac{1}{4}(2)^{k-1}$

Here,

$a_k=\dfrac{1}{4}(2)^{k-1}$        ...(i)

We know that, kth term of a GP is

$a_k=a_1(r)^{k-1}$        ...(ii)

From (i) and (ii), we get

$a_1=\dfrac{1}{4}$ and $r=2$

Therefore, the correct option is C.