Thats really bad! Just ran into a similar one which seems to show the very same error - see http://www.ptc.com/forums/viewtopic.php?t=7133&sid=8af43b7fb8d482efe484cb4dd79efe92 I don't know if the faulty result of INT(x*ln(x),x) has the same roots. Its a shame the PTC will not correct such bad and serious errors immediately. They seem to be known for quite some time and the bug is already fixed in next maintainance release. I would expect an immediate hotfix for all customers when something like that shows up. For me its a great difference if the program "simply" refuses to solve or evaluate an expression or is not able to simplify enough or if it delivers a result you should be able to rely on and than you have to find out its wrong. Regards Werner
