The value of C in Rolle’s theorem for the function \(f(x) = e^{x}\sin x\), \(x \in [0, \pi]\), is:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → \(\displaystyle\frac{3\pi}{4}\)
f is continuous on \([0, \pi]\) and differentiable on \((0, \pi)\), and
\(f(0) = e^{0}\sin 0 = 0\)
\(f(\pi) = e^{\pi}\sin\pi = 0\)
So Rolle’s theorem applies: there is a C in \((0, \pi)\) with \(f'(C) = 0\).
\(f'(x) = e^{x}\sin x + e^{x}\cos x = e^{x}(\sin x + \cos x)\)
Since \(e^{x} \ne 0\),
\(\sin C + \cos C = 0\)
\(\tan C = -1\)
In \((0, \pi)\) this gives
\( \displaystyle C = \frac{3\pi}{4} \)
Note: This topic was not in the CUET 2026 syllabus.