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## Re: [Axiom-developer] How can I get the constant term in a polynomial

**From**: |
Martin Rubey |

**Subject**: |
Re: [Axiom-developer] How can I get the constant term in a polynomial |

**Date**: |
18 Dec 2006 09:38:12 +0100 |

**User-agent**: |
Gnus/5.09 (Gnus v5.9.0) Emacs/21.4 |

Francois Maltey <address@hidden> writes:
>* I want to simplify sin ((a+1)*(b+%pi)) = sin (a*b + a*%pi + b + %pi)*
>* to - sin (a*b + a*%pi + b)*
>* *
>* I can get the coefficient of %pi in the numerator of the argument of sin x.*
>* *
>* MP ==> SparseMultivariatePolynomial(R, K)*
>* K ==> Kernel F*
>* Z ==> Integer*
>* *
>* kpi : K := retract(pi())@K -- the constant %pi*
>* *
>* coeffPi : MP -> Z*
>* coeffPi x ==*
>* R has retractIfCan : R -> Union(Integer,"failed") =>*
>* ccz := retractIfCan (coefficient (p, kpi, 1))@Union(Z, "failed")*
>* ccz case Integer => ccz::Integer*
>* 0*
>* *
>* In this example this coefficient is (a+1).*
>* *
>* I don't want the all coefficient a+1, but only the constant term, 1 in R.*
So you want the constant term of a SparseMultivariatePolynomial(R, K), that is,
a polynomial with variables being in K an coefficients in R.
I guess you want to use
coefficient(p,0$IndexedExponents(Symbol))
Martin