Question

In the expansion of $\frac{1 - 2x + 3x^{2}}{e^{x}}$, the coefficient of $x^{5}$ will be.

• A. $\frac{71}{120}$
• B. $- \frac{71}{120}$
• C. $\frac{31}{40}$
• D. $- \frac{31}{40}$

Answer 1

Answer: (B)

$- \frac{71}{120}$

Answer 2

$\log_{a}x$

$(a > 0)$

$x \neq 1$ The coefficient of $x \neq 0$

$a \geq e$

$\log_{e}2 + \log_{e}\left( 1 + \frac{1}{2} \right) + \log_{e}\left( 1 + \frac{1}{3} \right) + .... + \log_{e}\left( 1 + \frac{1}{n - 1} \right)$.