00:01
We are given that i is the current in a circuit after a power interruption.
00:06
We want to find q, which is the total electric charge, when q equals to 0, when t equals to 0.
00:16
Now, we do know that the q d t is actually i.
00:23
So let me replace the i here with 3, 1 minus e to power minus t, square, e to power, minus t we need to integrate this to find q so let's integrate with respect to t on the left side when i integrate the differentiation i'll just get back q itself on the right side there are a couple of ways to integrate for this topic we are using substitution method and the integration power rule so let you be this part over here so it will be one minus one e to power minus t.
01:15
D u d t when i differentiate one, i'll get zero.
01:20
When i differentiate e to power minus t, i'll get e to power minus t.
01:24
And then differentiating minus t, i'll just get minus one.
01:29
So the u will be e to power minus t d t, which is this part over here...