Stability Analysis for G(s) and P(s)

[Logarythmic]

Homework Statement

I have a transfer function G(s) = \frac{1}{s^2} and a PI controller P(s) = 6 \left( 1 + \frac{1}{s} \right).

How do I check for stability? Just use 1 + P(s)G(s) = 0 and check the roots?

 

[CEL]

Yes, if all the roots have a negative real part the system is stable.