Q110 / 180 · KCET 2018 · Mathematics
If \( f(x)=|\cos x-\sin x| \), then \( f^{\prime}\left(\frac{\Pi}{6}\right) \) is equal to
- Correct answerA\( -\frac{1}{2}(1+\sqrt{3}) \)
- B\( \frac{1}{2}(1+\sqrt{3}) \)
- C\( -\frac{1}{2}(1-\sqrt{3}) \)
- D\( \frac{1}{2}(1-\sqrt{3}) \)
Solution
Given that, $f(x)=|\cos x-\sin x|$
So, $f^{\prime}(x)=-\sin x-\cos x$
At $x=\frac{\Pi}{6}$, we have
$f^{\prime}\left(\frac{\Pi}{6}\right)=-\sin \left(\frac{\Pi}{6}\right)-\cos \left(\frac{\Pi}{6}\right)$
$=-\frac{1}{2}-\frac{\sqrt{3}}{2}=\frac{-1}{2}(1+\sqrt{3})$
Hence, the correct answer is option: 'A'.