WIP #930 iterative functions for TrigExpand

Author: axkr

symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/reflection/system/TrigExpand.java

@@ -19,7 +19,6 @@
 import org.matheclipse.core.expression.ImplementationStatus;
 import org.matheclipse.core.expression.S;
 import org.matheclipse.core.interfaces.IAST;
-import org.matheclipse.core.interfaces.IASTAppendable;
 import org.matheclipse.core.interfaces.IExpr;
 import org.matheclipse.core.interfaces.IInteger;
 import org.matheclipse.core.visit.VisitorPlusTimesPowerReplaceAll;
@@ -109,8 +108,12 @@ private IExpr expandPlus(IAST ast, IAST plusAST) {
         return expandCoshSinhPlus(plusAST, true);
       } else if (ast.isAST(S.Csch, 2)) {
         return expandCschPlus(plusAST, 1);
+      } else if (ast.isAST(S.Coth, 2)) {
+        // Cosh(x) / Sinh(x)
+        return F.Divide(expandCoshSinhPlus(plusAST, true), expandCoshSinhPlus(plusAST, false));
       } else if (ast.isTanh()) {
-        return expandTanhPlus(plusAST, 1);
+        // Sinh(x) / Cosh(x)
+        return F.Divide(expandCoshSinhPlus(plusAST, false), expandCoshSinhPlus(plusAST, true));
       }
       return F.NIL;
     }
@@ -298,28 +301,6 @@ private static IExpr expandSechPlus(IAST plusAST, int startPosition) {
           F.Power(F.Plus(F.Times(F.Cosh(b), F.Cosh(a)), F.Times(F.Sinh(a), F.Sinh(b))), F.CN1)));
     }
 
-    /**
-     * <code>Tanh(a+b+c+...)</code>
-     *
-     * @param plusAST
-     * @param startPosition
-     * @return
-     */
-    private static IExpr expandTanhPlus(IAST plusAST, int startPosition) {
-      IASTAppendable result = F.TimesAlloc(2);
-      IExpr lhs = plusAST.get(startPosition);
-      if (startPosition == plusAST.size() - 2) {
-        // (Tanh(x)+Tanh(y)) / (1+Tanh(x)*Tanh(y))
-        IExpr rhs = plusAST.get(startPosition + 1);
-        result.append(Plus(F.Tanh(lhs), F.Tanh(rhs)));
-        result.append(F.Power(Plus(F.C1, Times(F.Tanh(lhs), F.Tanh(rhs))), F.CN1));
-      } else {
-        result.append(Plus(F.Tanh(lhs), expandTanhPlus(plusAST, startPosition + 1)));
-        result.append(F.Power(
-            Plus(F.C1, Times(F.Tanh(lhs), expandTanhPlus(plusAST, startPosition + 1))), F.CN1));
-      }
-      return result;
-    }
   }
 
   public TrigExpand() {}

symja_android_library/matheclipse-core/src/test/java/org/matheclipse/core/system/LowercaseTestCase.java

@@ -25704,12 +25704,18 @@ public void testTrigExpand() {
     check("TrigExpand(Sinh(a+b+c))", //
         "Cosh(b)*Cosh(c)*Sinh(a)+Cosh(a)*Cosh(c)*Sinh(b)+Cosh(a)*Cosh(b)*Sinh(c)+Sinh(a)*Sinh(b)*Sinh(c)");
 
+    check("TrigExpand(Coth(a+b))", //
+        "(Cosh(a)*Cosh(b))/(Cosh(b)*Sinh(a)+Cosh(a)*Sinh(b))+" //
+            + "(Sinh(a)*Sinh(b))/(Cosh(b)*Sinh(a)+Cosh(a)*Sinh(b))");
+
     check("TrigExpand(Tanh(a+b))", //
-        "Tanh(a)/(1+Tanh(a)*Tanh(b))+Tanh(b)/(1+Tanh(a)*Tanh(b))");
+        "(Cosh(b)*Sinh(a))/(Cosh(a)*Cosh(b)+Sinh(a)*Sinh(b))+" //
+            + "(Cosh(a)*Sinh(b))/(Cosh(a)*Cosh(b)+Sinh(a)*Sinh(b))");
     check("TrigExpand(Tanh(a+b+c))", //
-        "Tanh(a)/(1+(Tanh(a)*Tanh(b))/(1+Tanh(b)*Tanh(c))+(Tanh(a)*Tanh(c))/(1+Tanh(b)*Tanh(c)))+Tanh(b)/((\n"
-            + "1+Tanh(b)*Tanh(c))*(1+(Tanh(a)*Tanh(b))/(1+Tanh(b)*Tanh(c))+(Tanh(a)*Tanh(c))/(1+Tanh(b)*Tanh(c))))+Tanh(c)/((\n"
-            + "1+Tanh(b)*Tanh(c))*(1+(Tanh(a)*Tanh(b))/(1+Tanh(b)*Tanh(c))+(Tanh(a)*Tanh(c))/(1+Tanh(b)*Tanh(c))))");
+        "(Cosh(b)*Cosh(c)*Sinh(a))/(Cosh(a)*Cosh(b)*Cosh(c)+Cosh(c)*Sinh(a)*Sinh(b)+Cosh(b)*Sinh(a)*Sinh(c)+Cosh(a)*Sinh(b)*Sinh(c))+"//
+            + "(Cosh(a)*Cosh(c)*Sinh(b))/(Cosh(a)*Cosh(b)*Cosh(c)+Cosh(c)*Sinh(a)*Sinh(b)+Cosh(b)*Sinh(a)*Sinh(c)+Cosh(a)*Sinh(b)*Sinh(c))+"//
+            + "(Cosh(a)*Cosh(b)*Sinh(c))/(Cosh(a)*Cosh(b)*Cosh(c)+Cosh(c)*Sinh(a)*Sinh(b)+Cosh(b)*Sinh(a)*Sinh(c)+Cosh(a)*Sinh(b)*Sinh(c))+"//
+            + "(Sinh(a)*Sinh(b)*Sinh(c))/(Cosh(a)*Cosh(b)*Cosh(c)+Cosh(c)*Sinh(a)*Sinh(b)+Cosh(b)*Sinh(a)*Sinh(c)+Cosh(a)*Sinh(b)*Sinh(c))");
 
     check("TrigExpand(Csc(a+b+c))", //
         "1/(Cos(b)*Cos(c)*Sin(a)+Cos(a)*Cos(c)*Sin(b)+Cos(a)*Cos(b)*Sin(c)-Sin(a)*Sin(b)*Sin(c))");

symja_android_library/matheclipse-core/src/test/java/org/matheclipse/core/system/SimplifyTest.java

@@ -757,7 +757,7 @@ public void testTrigSimplifyTR10() {
 
     tr10 = TrigSimplifyFu.tr10(F.Sin(F.Plus(F.a, F.b, F.c)));
     assertEquals(tr10.toString(), //
-        "Sin(a)*Cos(b)*Cos(c)+Sin(a)*-Sin(b)*Sin(c)+Cos(a)*Cos(c)*Sin(b)+Cos(a)*Cos(b)*Sin(c)");
+        "Cos(c)*Cos(b)*Sin(a)+Cos(c)*Cos(a)*Sin(b)+Cos(a)*Cos(b)*Sin(c)+-Sin(a)*Sin(b)*Sin(c)");
   }
 
   @Test