Interpretation maxima %rnum_list

Question

I don't really understand how to interpret the output of the function solve() in Maxima. For instance, I have to sove this:

solve(a1*x1/(a1*x1+a2*x2)-r1*x1/(r1*x1+r2*x2),[x1,x2]);
[[x1=%r1,x2=0],[x1=0,x2=%r2]]

Are %r1 and %r2 2 constants ?

Thank you.

Answer 1

From the docs:

The symbols %r1, %r2, …, are introduced as needed to represent arbitrary parameters in the solution; these variables are also appended to the list %rnum_list.