divrem

["Rosita Wachenchauzer" <rosita@favaloro.edu.ar>]

When the main variable is x, divrem works properly:

? p=-16*x^4+(y+1)*x^2

%2 = -16*x^4 + (y + 1)*x^2

? q=x^2-1

%3 = x^2 - 1

? divrem(p,q)

%4 = [-16*x^2 + (y - 15), y - 15]~

? reorder

%5 = [x, y, p, q]

?

but when the main variable is NOT x, then it does not work properly:

? p

%7 = -16*y^4 + (x + 1)*y^2

? q

%8 = y^2 - 1

? reorder

%9 = [y, x, p, q]

? divrem(p,q)

%10 = [(-16*y^6 + (x + 17)*y^4 + (-x - 1)*y^2)/(y^4 - 2*y^2 + 1), 0]~

?