Find d/dx (x² sin x) by product rule:
- 2x cos x
- 2x sin x
- x² cos x + 2x sin x
- x² + sin x
Show answer and solution
Correct answer: C. x² cos x + 2x sin x
**Product rule:** (fg)' = f'g + fg'.
With f = x², g = sin x: derivative = 2x × sin x + x² × cos x = 2x sin x + x² cos x.