i have this maths question i can't get the right answer although i've tried so many times. please help :)

A charged capacitor is connected to a circuit. The charge on the capacitor changes over time according to the equation: q (t) = Qef(t) where: . q (t) is the ammount of charge accumulated at time t . Q is the initial charge stored in the capacitor . f (t) is a function of time The current, I (t), from the discharging capacitor can be calculated as I (t) = da(t) dt For this specific circuit, f (t) - Itt 0. If Q = 1.5 Coulombs, what is the current at t = 3.1 s? Note that you will have to use the chain rule to evaluate the derivative. Give your answer to 2 decimal places