Need help finding voltage across a capacitor in an RC circuit?

sl02ggp
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1. Homework Statement

Find the voltage across a capacitor in an RC Circuit, using [V]_{}[/c] (0) = 1, [V]_{}[/i] n(t)=t.

2. Homework Equations
dV/dt = (1/RC)(V)=(1/RC)([V]_{}[/in])


3. The Attempt at a Solution
New to this site: I honestly don't know where to start. Done well in Calculus. Feel DifEq is like a breed of its own..aha

I know you have to use this type of an equation: VC = V0(1− e−t /τ ) where τ = RC and V0 is the initial voltage
 
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I'm a little confused by your equations..

In general the voltage across a series RC circuit will decay exponentially, on a time constant determined by the value of RC.

The voltage across a resistor is:

V_R = IR = R\frac{dQ}{dt}

The voltage across a capacitor is:

V_C = Q/C

Knowing this, you should be able to set up a simple differential equation which will provide the answer you desire.
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...

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