i understand the markscheme for the 1st way, but i don't get the 2nd way
the capacitor is charging and discharging so should use V for one value, then pick a 2nd Voltage within one of the charging or discharging cycles which is used at the end C=Q/V , over a change in time (that should be the change)
instead they use they use a change in voltage i dont understand. the voltage should never decrease below 3.5 ON THE CAPACITOR
