floor(log(4)/log(2)) = 1 ??

• Subject: floor(log(4)/log(2)) = 1 ??
• From: Robert Dodier
• Date: Sat, 26 Apr 2008 21:13:24 -0600

On 4/26/08, Oliver Kullmann <O.Kullmann at swansea.ac.uk> wrote:

> To add further to the log-problems:
>
>  is(2^(log(4)/log(2)) = 4);
>  Evaluation took 0.0030 seconds (0.0194 elapsed) using 1.508 KB.
>  (%o1)                                          false
>
>  I'm using 5.15.0.
>
>  I think this definitely is a bug: The result may be "unknown",
>  but not false.

Maxima recognizes "=" as literal identity, not equivalence.
If two expressions a and b are equivalent, but arranged differently,
is(a = b) returns false, while is(equal(a, b)) returns true.
That is the case here.

is (equal (2^(log(4)/log(2)), 4)); => true

HTH

Robert Dodier

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