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Solve drops an equation of a conjunction once it has a parameter: x = y and x = 2 is { y } #1680
Description
Measured on master fb520e20. Solve on a conjunction of equations is right while the equations are closed, and keeps only the first once another symbol appears:
.Solve("x") |
answer | right answer |
|---|---|---|
x = 2 and x = 3 |
{ } |
{ } |
x + 1 = 3 and x - 1 = 1 |
{ 2 } |
{ 2 } |
x = y and x = 2 |
{ y } \/ { } |
{ 2 } where y = 2, else { } |
x + y = 3 and x - y = 1 |
{ 3 - y } \/ { } |
{ 2 } where y = 1, else { } |
x^2 = 4 and x = y |
{ 2, -2 } \/ { } |
{ y } where y^2 = 4, else { } |
Each wrong answer is the first equation's solution set with the second ignored: at y = 0, x = 0 does not satisfy x = 2.
x^2 = 4 and not x = 2 already keeps a condition that its members leave undecided (BREAKING-CHANGES.md, A listed solution set is filtered by a decided condition). The same should hold here: a member at which the second equation is undecided keeps that equation as its condition.
Found while answering #1673.
Activity
An undecided member of an intersection stays in it (ASC-Community#1681)