 
 
 
11.7.1  Roots and poles of a rational function
The froot command finds roots and
poles of a rational function.
Examples
| froot((x^5-2*x^4+x^3)/(x-2)) | 
Hence, for  F(x)=x5−2x4+x3/x−2:
- 
1 is a root of multiplicity 2,
- 0 is a root of multiplicity 3,
- 2 is a pole of order 1.
| froot((x^3-2*x^2+1)/(x-2)) | 
|  | | |  | ⎡ ⎢
 ⎢
 ⎣
 | 1,1, |  | ,1, |  | ,1,2,−1 | ⎤ ⎥
 ⎥
 ⎦
 | 
 |  |  |  |  |  |  |  |  |  |  | 
 | 
Remark.
To find the complex roots and poles, put Xcas in complex mode
(check the complex box in the CAS configuration, red button
giving the state line; see Section 2.5.5).
Example
Input in complex mode:
 
 
