Solving for 3dB frequency appproximations

[area5x1]

Homework Statement

I have the transfer function:

F(s) = s^3 / ((s+12)(s+550)(s+680))

Find the lower cutoff frequency (3dB point)

Homework Equations

s = jw

The Attempt at a Solution

I set the equation equal to 1/sqrt(2), use s = jw, and try to solve for the frequency. Now I'm just supposed to "Put it into your calculator and off I go", but what exactly do I put into my calculator? I have a Ti-84, is that able to solve these types of problems?

What's throwing me off is the imaginary term 'j', I'm not exactly sure what to do with it when solving this polynomial.

 

[rude man]

You need to find the magnitude of a complex number.

It's |a + jb| = sqrt(a^2 + b^2).

So find a and b for your transfer function and set the magnitude = 1/sqrt(2).