public static Tuple <MathObject, int> CoefficientMonomialGpe(this MathObject u, MathObject x)
{
if (u == x)
{
return(Tuple.Create((MathObject)1, 1));
}
if (u is Power &&
(u as Power).bas == x &&
(u as Power).exp is Integer &&
((u as Power).exp as Integer).val > 1)
{
return(Tuple.Create((MathObject)1, ((u as Power).exp as Integer).val));
}
if (u is Product)
{
var m = 0;
var c = u;
foreach (var elt in (u as Product).elts)
{
var f = elt.CoefficientMonomialGpe(x);
if (f == null)
{
return(null);
}
if (f.Item2 != 0)
{
m = f.Item2;
c = u / (x ^ m);
}
}
return(Tuple.Create(c, m));
}
if (u.FreeOf(x))
{
return(Tuple.Create(u, 0));
}
return(null);
}
public static Tuple <MathObject, int> CoefficientMonomialGpe(this MathObject u, MathObject x)
{
if (u == x)
{
return(Tuple.Create((MathObject)1, 1));
}
if (u is Power &&
((Power)u).bas == x &&
((Power)u).exp is Integer &&
((Integer)((Power)u).exp).val > 1)
{
return(Tuple.Create((MathObject)1, ((Integer)((Power)u).exp).val));
}
if (!(u is Product))
{
return(u.FreeOf(x) ? Tuple.Create(u, 0) : null);
}
int m = 0;
MathObject c = u;
foreach (Tuple <MathObject, int> f in ((Product)u).elts.Select(elt => elt.CoefficientMonomialGpe(x)))
{
if (f == null)
{
return(null);
}
if (f.Item2 == 0)
{
continue;
}
m = f.Item2;
c = u / (x ^ m);
}
return(Tuple.Create(c, m));
}