7.98 Bug in limit(c/x/ln(x)) in Maple V.4 and Maple V.5 (13.8.97)

7.98.1 Andreas Jung

There is a sign bug in limit in the following cases (Maple V Release 4 under Solaris on a Sun workstation):

> limit(42/x/ln(x), x=0, right); 
                                   -infinity
 

Ok, that’s right. But:

> limit(c/x/ln(x), x=0, right); 
                              signum(c) infinity
 

The correct result should be -signum(c)*infinity. (Note that not the complex limit should be taken, but the real one). Interestingly, applying a minus sign has no influence on the result:

> limit(-c/x/ln(x), x=0, right); 
                              signum(c) infinity
 

So the result isn’t always wrong. It seems as if the numerator isn’t completely considered if it contains a variable. For example, try 17^e instead of c.

Assuming c to be real has no effect.

It is corrected with Maple 6. (U. Klein)