I've a third degree polynomial (in $s$):
I need to find the roots of the polynomial, so I can use the code:
Solve[a*s^3 + b*s^2 + c*s + d == 0, s]
Now, there are three solutions because it is a third degree polynomial.
Now, the question: I need to find the condition for which all three of the roots of the polynomial have a real part that is strictly smaller then zero. Can I find that condition?