If the voltage across a 5 farad capacitor is 2te^(-3t) V, the current through the capacitor is
- A. 30te^(-3t) A
- B. -30te^(-3t) A
- C. 30te^(-3t) - 10e^(-3t) A
- D. 10e^(-3t) - 30te^(-3t) A
Answer: D. 10e^(-3t) - 30te^(-3t) A
Explanation: Capacitor current i(t) = C dv/dt = 5 d/dt[2t e^(-3t)] = 5 [2 e^(-3t) - 6t e^(-3t)] = 10 e^(-3t) - 30t e^(-3t) A.