The topic of this problem is energy storage elements.

And the problem is to find i(t) in the circuit show below.

The circuit is a two node circuit with a node at the top and a node at the bottom,

and has a current source i(t), that's the current that we're looking for.

It has a capacitor and a resistor as well.

We know if we use Kirchhoff's Current Law at the top node, and

some of the currents perhaps into that top node, and the sum of those currents is

going to be i(t) because i(t) is flowing into that node from the left-hand side.

We have minus IC of T And

then also minus i sub r of t.

And the sum of those is equal to zero, in Kirchhoff's current law.