CMI-2020-DataScience-A: 17

Question

The identity

$$\frac{1}{(1-2r)}=\displaystyle\sum^{\infty} _{k=0} (2r)^k $$

is true

• A. if and only if $r\neq \frac{1}{2}$
• B. if and only if $0\leq r < \frac{1}{2}$
• C. if and only if $-\frac{1}{2} \leq r<\frac{1}{2}$
• D. if and only if $-\frac{1}{2}<r<\frac{1}{2}$

Answer 1