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Homework Statement
We are given K1 = 0. So the answer should be in the form of V(x) = K2e^(-t/z)
Homework Equations
V=IR
V(x) = K1 + K2e^(-t/z)
V(infinity) = K1
V(0+) = K1 + K2
z = RC
The Attempt at a Solution
I draw the circuit for t = 0- and find the voltage across the capacitor. Vc(0-) = 27/12*4 = 9V
Now I draw the circuit for t = 0+ with the capacitor as a voltage source. I apply KVL to get the following:
4i1 = 27
i2 = 0
-9 + 2i3 + 4i3 = 0
Vo(0+) = -3V
We know K1 = 0, so I don't draw the circuit for Vo(infinity)
V(0+) = -3 = K2
z = RC.
Now I get the thevenin resistance across the capacitor; ignoring the short circuit I have: ( 1/(1/4+1/4)+2)=4k ohm
So z = 4000 * 350 * 10^-6 = 1.4
But my answer is wrong: V(t) = -3e^(-t/1.4)