From aa2166ed9939ff9f306bd54802a87794140a9f8e Mon Sep 17 00:00:00 2001
From: axexlck <axelclk@gmail.com>
Date: Sun, 12 Nov 2023 03:25:15 +0100
Subject: [PATCH] WIP #856 improve Together - handle "inverse denominator
 number"

>> 1/(sqrt[7] - 2 sqrt[2]) + 1/(sqrt[7] + 2 sqrt[2]) // Together
-2*Sqrt(7)
---
 .../src/main/java/org/matheclipse/core/builtin/Algebra.java | 6 +++---
 .../org/matheclipse/core/system/LinearAlgebraTestCase.java  | 2 +-
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/builtin/Algebra.java b/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/builtin/Algebra.java
index 59717f50d1..dd3f4a3d08 100644
--- a/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/builtin/Algebra.java
+++ b/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/builtin/Algebra.java
@@ -4365,9 +4365,6 @@ private static IExpr togetherPlus(IAST plusAST) {
         return F.C0;
       }
       if (!exprDenominator.isOne()) {
-        if (exprDenominator.isMinusOne()) {
-          return exprNumerator.negate();
-        }
         try {
           IExpr[] result = cancelGCD(exprNumerator, exprDenominator);
           if (result != null) {
@@ -4380,6 +4377,9 @@ private static IExpr togetherPlus(IAST plusAST) {
         } catch (JASConversionException jce) {
           LOGGER.debug("Together.togetherPlus()", jce);
         }
+        if (exprDenominator.isNumber()) {
+          return exprDenominator.inverse().times(exprNumerator);
+        }
         return F.Times(exprNumerator, F.Power(denom, -1));
       }
       return exprNumerator;
diff --git a/symja_android_library/matheclipse-core/src/test/java/org/matheclipse/core/system/LinearAlgebraTestCase.java b/symja_android_library/matheclipse-core/src/test/java/org/matheclipse/core/system/LinearAlgebraTestCase.java
index 563182f05e..459a400ea3 100644
--- a/symja_android_library/matheclipse-core/src/test/java/org/matheclipse/core/system/LinearAlgebraTestCase.java
+++ b/symja_android_library/matheclipse-core/src/test/java/org/matheclipse/core/system/LinearAlgebraTestCase.java
@@ -17,7 +17,7 @@ public LinearAlgebraTestCase(String name) {
 
   public void testAdjugate() {
     check("Adjugate({{E^5, 1, 3 - 2*I}, {1 + I, Pi/2, 5}, {0, 1, -4}})", //
-        "{{2*(-5/2-Pi),7-I*2,(3/2-I)*(30/13+I*20/13-Pi)},\n" //
+        "{{-2*(5/2+Pi),7-I*2,(3/2-I)*(30/13+I*20/13-Pi)},\n" //
             + " {4+I*4,-4*E^5,5*(1+I*1/5-E^5)},\n" //
             + " {1+I,-E^5,1/2*(-2-I*2+E^5*Pi)}}");
     // https://en.wikipedia.org/wiki/Adjugate_matrix