krac2 continuous SISO system limit feedback gain

## Syntax

    g = krac2(sys)

## Arguments

sys
  A SISO linear dynamical system, in state space, transfer function or zpk representations, in continuous or discrete time.
g

  constant

## Description

`krac2(sys)` computes the gains `g` such that the system `sys` feedback by g (`sys/.g`) has 2 real equal poles.

## Examples

    h = syslin('c', 352*poly(-5,'s') / poly([0,0,2000,200,25,1],'s','c'));
    clf
    evans(h,100)
    g = krac2(h)
    hf1 = h/.g(1); roots(hf1.den)
    hf2 = h/.g(2); roots(hf2.den)

## See also

- evans
- kpure

## History

6.0

handling zpk representation