Q58 / 155 · WBJEE 2016 · Mathematics
In the expansion of $(x-1)(x-2) \ldots(x-18)$ the coefficient of $x^{17}$ is
- A684
- Correct answerB-171
- C171
- D-342
Solution
Coefficient of $x^{17}$ in $(x-1)(x-2) \ldots(x-18)$
$$
\begin{array}{l}
=-(1+2+3+\ldots+16) \\
=-(171)=-171
\end{array}
$$
Hence, the correct answer is option: 'B'.