How to draw the root locus of two negative real open-loop zeros and two complex open-loop poles

Generally speaking, this kind of problem is a typical circle root locus
After the separation point is found, the center and radius of the circle can be found according to the geometric relationship
If we ask the direction of the root locus, we start from the open-loop pole, draw a circle, enter the real axis, and separate to go to two open-loop zeros
Hope to help the landlord

What are open loop poles and closed loop poles
Learning from modern control system, I am confused by open-loop poles, closed-loop poles, open-loop zeros, closed-loop zeros, open-loop roots, closed-loop roots, and ask the great God to solve the puzzle!

The so-called open-loop or closed-loop refers to the zeros and poles of its transfer function. Closed loop transmission = g (s) | (1 + open-loop transmission). | denotes division

Limit zero point theorem
It is proved that the equation x + 3x - 1 = 0 has at least one positive heel less than 1
It is proved that let f (x) = the third power of X + 3x-1 be continuous by F (x) at (0,1)
And f (0) = - 1
F(1)=3
F(0)XF(1)

Elementary functions are continuous in their domain of definition
In this problem, X ∈ R and [0,1] belong to its domain of definition, and the title "prove that the equation x to the third power + 3x-1 = 0 has at least one positive heel less than 1." that's right. To prove that there is a positive root less than 1 means that you need to prove the existence of the root of X in [0,1]

How to draw the root locus of two negative real open-loop zeros and two complex open-loop poles