How Is Current Calculated in a Circuit with Charge Function q(t)?

[JFonseka]

Homework Statement

The total charge that has entered a circuit element is q(t)=2(3 − e^{-4t}) when t≥0 and
q(t)=0 when t<0. Determine the current in this circuit element for t≥0.

Homework Equations

Differentiation

The Attempt at a Solution

i(t) = 2(4e^{-4t}) + 3 - e^{-4t}

i(t) = 7e^{-4t} + 3

However the answer says 8e^{-4t}

What have I done wrong?

 

[JFonseka]

Nvm. Dumb mistake, just realized. Solved.