NDA 2017
- Exam
- NDA
- Year
- 2017
- Subject
- Mathematics
- Chapter
- Sequences and Series
NDA 2017 · Mathematics · Sequences and Series
The value of (1)/( _3 e)+(1)/( _3 e^2)+(1)/( _3 e^4)+ . up to...
The value of . up to infinite terms is
Options
- A
- B
- C
- D
Correct answer
A.
Step-by-step solution
\frac{1}{\log _3 \mathrm{e}}+\frac{1}{\log _3 \mathrm{e}^2}+\frac{1}{\log _3 \mathrm{e}^4}+\ldots=\frac{1}{\log _3 \mathrm{e}}+\frac{1}{2 \log _3 \mathrm{e}}+\frac{1}{4 \log _3 \mathrm{e}}+\ldots \cdot\left(\right. Since, \left.\log _{\mathrm{a}} \mathrm{b}=\frac{1}{\log _{\mathrm{b}} \mathrm{a}}\right)=\log _{\mathrm{e}} 3\left(1+\frac{1}{2}+\frac{1}{4}+\ldots.\right)=\log _{\mathrm{e}} 3\left(\frac{1}{1-\frac{1}{2}}\right)\left(\because 1, \frac{1}{2}, \frac{1}{4} \ldots\right..