Perhaps delta function or inverse Laplace transform?

EvLer
Hello everyone,
i have this question and not even sure how to approach it:

$$\frac {di}{dt}+4i+3\int_{0^-}^t{i(z)dz = 12(t-1)u(t-1)$$

and $$i(0^-) = 0$$

find $$i(t)$$

last topics we covered were laplace transforms (and inverse) and dirac delta function.
At least some hint to get me started would be a great help.

EDIT:
oh, and again u(t) = 1 for t >= 0 and u(t) = 0 elsewhere.

Last edited:

Homework Helper
I would get rid of the integral by taking the derivative of the entire equation - which gives you a second order differential equation and leads you into the LaPlace transform.

thanks for replies, as i looked further through the book, we actually have an entry in the table for this integral, but what do I do with $$i$$ for Laplace transform? it does not have u(t)...