If \(f(x) = x^3\log_e x\), then \(f''(e^2)\) is equal to
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → \(17e^2\)
By the product rule:
\( \displaystyle f'(x) = 3x^2\log_e x + x^3 \cdot \frac{1}{x} = 3x^2\log_e x + x^2 \)
Differentiating again, with the product rule on the first term:
\( \displaystyle f''(x) = 3\left(2x\log_e x + x^2 \cdot \frac{1}{x}\right) + 2x \)
\(f''(x) = 6x\log_e x + 3x + 2x = 6x\log_e x + 5x\)
At \(x = e^2\), \(\log_e e^2 = 2\):
\(f''(e^2) = 6e^2(2) + 5e^2 = 12e^2 + 5e^2 = 17e^2\)