Absolute value: sometimes CAS is very clever, sometimes not!

[compsystems]

One problem with xcas is that it often assumes ( = ) as a comparison operator ( == ). I suggest that this feature be activated or not by means of a flag.

https://xcas.univ-grenoble-alpes.fr/foru...=19&t=2105

goto advanced graphing app
X, Y RETURNS [0,0] // ok, X and Y by default are in zeros
V1(X,Y):=X-2*Y=7; V2(X,Y):=5*X-3*Y=2; returns [0,0] // although the output is zero [0,0], the definition is correct. press [symb] key // V1:X-2*Y=7
right(V1) returns 0
0-2*0=7, 5*0-3*0=2
0=7, 0=2 // should not be evaluated, the symbolic expression should be left
0 => FALSE, 0 => FALSE

another problem is that he interprets expressions as if they were literal comparison

Simplify flag: maximum
assume(x,symbol);
answer:=domain((1/(x+1)),x); returns 1 // of true // x ≠ -1
answer:=domain((1/(x+1)),x); returns x ≠ -1