Bug or feature: IsDefined[] and intersection of lines

hjbortol shared this question 10 years ago
Answered

In the input field, type:


x = 1

y = 1


Then, construct the intersection of these two lines (the point A).


In the input field, type


IsDefined[A]


The answer is true.


Now change the equation "y = 1" to "x = 2". The Algebra View shows:


A = undefined


but IsDefined[A] still returns true.


Curiously, IsDefined[] works well with intersection of segments.


Is this behaviour correct?


Thanks in advance, Humberto.

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Fixed - 3.1.155.0 online now

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