Find the frequency in an LRC circuit

[tony873004]

w=w₀^2 - alpha^2
and then take the square root of this.

But I keep getting a negative number and I can't put this under the root symbol. I remeber he discussed this in class but I can't find it in my notes. How do I deal with the negative so I can find the frequency?

 

[Redbelly98]

Not all RLC circuits will oscillate. If R, L, & C are such that
alpha > w0
you get the situation you are describing.