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integrate(logarc(atan2(y,x)),y) -> Divison by zero #4131

Open rtoy opened 2 months ago

rtoy commented 2 months ago

Imported from SourceForge on 2024-07-09 17:45:07 Created by crategus on 2010-07-09 18:57:27 Original: https://sourceforge.net/p/maxima/bugs/2030

When we try to integrate the equivalent logarithmic expression for atan2 we get an error:

(%i34) integrate(logarc(atan2(y,x)),x); Division by 0 -- an error. To debug this try: debugmode(true);

(%i35) integrate(logarc(atan2(y,x)),y); Division by 0 -- an error. To debug this try: debugmode(true);

The error occurs in ratint. ratint tries to integrate the following expression:

(%i36) expr; (%o36) -x^3/(%i*y^3+x*y^2+%i*x^2*y+x^3)

(%i37) integrate(expr,x); 0: (RATINT ((MTIMES SIMP) ((MEXPT SIMP) $X 3) ((MEXPT SIMP) ((MPLUS SIMP) ((MEXPT SIMP) $X 3) ((MTIMES SIMP) $%I ((MEXPT SIMP) $X 2) $Y) ((MTIMES SIMP) $X ((MEXPT SIMP) $Y 2)) ((MTIMES SIMP) $%I ((MEXPT SIMP) $Y 3))) -1)) $X) Division by 0 -- an error. To debug this try: debugmode(true);

Dieter Kaiser

rtoy commented 2 months ago

Imported from SourceForge on 2024-07-09 17:45:08 Created by crategus on 2010-07-09 18:59:42 Original: https://sourceforge.net/p/maxima/bugs/2030/#469c

Correcting the title.

rtoy commented 2 months ago

Imported from SourceForge on 2024-07-09 17:45:11 Created by crategus on 2010-07-09 18:59:42 Original: https://sourceforge.net/p/maxima/bugs/2030/#b04c