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11.1.22  Exact roots of a polynomial

The roots command finds roots of polynomials with their multiplicities.

Examples

Find the roots of P(x)=x5−2x4+x3.

roots(x^5-16*x^4+x^3)
     
⎡
⎢
⎢
⎢
⎢
⎢
⎢
⎣
3 √
7
+8
1
−3 √
7
+8
1
03
⎤
⎥
⎥
⎥
⎥
⎥
⎥
⎦
          

Find the roots of x10−15x8+90x6−270x4+405x2−243=(x2−3)5.

roots(x^10-15*x^8+90*x^6-270*x^4+405*x^2-243)
     
⎡
⎢
⎢
⎢
⎢
⎢
⎣
√
3
5
−√
3
5
⎤
⎥
⎥
⎥
⎥
⎥
⎦
          

Find the roots of t3−1.

roots(t^3-1,t)
     
⎡
⎢
⎢
⎢
⎢
⎢
⎢
⎢
⎢
⎣
    11
i √
3
−1
2
1
    
−i √
3
−1
2
1
⎤
⎥
⎥
⎥
⎥
⎥
⎥
⎥
⎥
⎦
          

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