Chapter 30, Problem Q30.11DQ

In Section 30.5 Kirchhoff’s loop rule is applied to an L-C circuit where the capacitor is initially fully charged and the equation −L (di/dt) = (q/C) = 0 is derived. But as the capacitor starts to discharge, the current increases from zero. The equation says L di/dt = −q/C, so it says L di/dt is negative. Explain how L di/dt can be negative when the current is increasing.