Question

$\frac{1}{5} + \frac{1}{2}.\frac{1}{5^{2}} + \frac{1}{3}.\frac{1}{5^{3}} + .....\infty =$

• A. $\log_{e}\frac{4}{5}$
• B. $\log_{e}\frac{\sqrt{5}}{2}$
• C. $2\log_{e}\frac{\sqrt{5}}{2}$
• D. None of these

Answer 1

Answer: (C)

$2\log_{e}\frac{\sqrt{5}}{2}$

Answer 2

$(1 + x + x^{2})e^{- x}$

$x^{2}$.