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limit doesn't check for zero coefficients in limit((a*x+1)/(a*x+2),x,inf) #2663

Open rtoy opened 2 months ago

rtoy commented 2 months ago

Imported from SourceForge on 2024-07-06 17:13:24 Created by macrakis on 2018-03-23 18:45:36 Original: https://sourceforge.net/p/maxima/bugs/3415

 limit((a*x+1)/(a*x+2),x,inf) => 1

If a=0, the correct answer is 1/2.

"5.41.0a_dirty" Maxima build date: "2017-10-24 09:10:17" Host type: "x86_64-w64-mingw32" Lisp implementation type: "SBCL" Lisp implementation version: "1.3.18"

rtoy commented 2 months ago

Imported from SourceForge on 2024-07-06 17:13:25 Created by macrakis on 2018-03-23 18:48:51 Original: https://sourceforge.net/p/maxima/bugs/3415/#587e

"5.41.0a_dirty" Maxima build date: "2017-10-24 09:10:17" Host type: "x86_64-w64-mingw32" Lisp implementation type: "SBCL" Lisp implementation version: "1.3.18"

rtoy commented 2 months ago

Imported from SourceForge on 2024-07-06 17:13:28 Created by macrakis on 2018-03-23 18:50:04 Original: https://sourceforge.net/p/maxima/bugs/3415/#fef2

Diff:


--- old
+++ new
@@ -1,3 +1,9 @@
-limit((a*x+1)/(a*x+2),x,inf) => 1
+     limit((a*x+1)/(a*x+2),x,inf) => 1

 If a=0, the correct answer is 1/2.
+
+"5.41.0a_dirty"
+Maxima build date: "2017-10-24 09:10:17"
+Host type: "x86_64-w64-mingw32"
+Lisp implementation type: "SBCL"
+Lisp implementation version: "1.3.18"
rtoy commented 2 months ago

Imported from SourceForge on 2024-07-06 17:13:32 Created by willisbl on 2022-12-05 20:21:14 Original: https://sourceforge.net/p/maxima/bugs/3415/#4842

When a is declared to be zero, this is fixed by Commit [37f222]. But when a hasn't been declared to be zero, we still have limit((a*x+1)/(a*x+2),x,inf) => 1

Arguably there is still a bug here, but I would say that limit((a*x+1)/(a*x+2),x,inf) => 1 is consistent with the rest of Maxima; for example `integrate(sin(a*x),x) = ...'