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Topic: Limit[ Sign[],x->Infinity ]
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Jack Goldberg

Posts: 53
Registered: 12/7/04
Limit[ Sign[],x->Infinity ]
Posted: Feb 16, 2001 4:27 AM
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I give you two examples using ver. 4.0 on a Mac and a unix system.

Limit[ Sign[x]*Sign[z],x->Infinity ]

yields Sign[z] which is good.

Limit[ Sign[x]+Sign[z],x->Infinity]

yields an expression too ugly to present to a wide audience, which is bad.
Its not a bug since

Limit[ Sign[x]+Sign[z],x->Infinity]//FullSimplify

yields 1+Sign[z] which is good.

I propose the name "buglet" to describe such "features" :-). By the way,
I tried some obvious variations on combinations of Sign[z] and Sign[x] and
found it pretty hard to predict the output.

Happy hunting


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