Question 6

Identify the following series as binomial expansion and find the sum. $1 - \dfrac{1}{2}\left(\dfrac{1}{4}\right) + \dfrac{1\cdot 3}{2!}\left(\dfrac{1}{4}\right)^2 - \dfrac{1\cdot 3\cdot 5}{3!}\left(\dfrac{1}{4}\right)^3 + \cdots$