Browse Questions

# The coefficient of $x^k$ in the expansion of $\large\frac{1-2x-x^2}{e^{-x}}$ is

$\begin {array} {1 1} (a)\;\frac{1-k-k^2}{k !} & \quad (b)\;\frac{k^2+1}{k !} \\ (c)\;\frac{1-k}{k !} & \quad (d)\;\frac{1}{k !} \end {array}$
Can you answer this question?

$(a)\;\frac{1-k-k^2}{k !}$
answered Nov 7, 2013 by