Two questions: The first one: Solving an equation:
solve(sin(x)==0,x)
gives the solution [a=pi]
but
solve([sin(x)==0,sin(x)==0],x)
raises to the somehow better solution [[a == pi*z425]] Where is the difference between the two equations?
A second one: A previous version of sage 5.something could solve
solve([sin(x)==0,-sin(x)==0],x)
However Sage 6.4.1 Returns an empty list.
