Q: If u = x³ + y³ where x = a cos t, y = b sin t, then du/dt =
(a)−3 a³ cos² t sin t + 3 b³ sin² t cos t
(b)3 a³ sin² t cos t + 3 b³ cos² t sin t
(c)3 b sin² t cos t + 3 a³ sin² t cos t
(d)−3 a³ sin t + 3 b³ cos² t sin t
Correct Answer: (a)
The correct answer is (b) '3 a³ sin² t cos t + 3 b³ cos² t sin t'. This question from the General Studies domain tests knowledge of Miscellaneous.