https://github.com/crowlogic/arb4j/issues/253

crowlogic · Dec 8, 2024 · ae84d8c · ae84d8c
1 parent 6e5f954
commit ae84d8c
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diff --git a/src/main/java/arb/expressions/nodes/Node.java b/src/main/java/arb/expressions/nodes/Node.java
@@ -331,4 +331,14 @@ public Node<D, R, F> cot()
     return apply("cot");
   }
 
+  public Node<D, R, F> sinh()
+  {
+    return apply("sinh");
+  }
+
+  public Node<D, R, F> cosh()
+  {
+    return apply("cosh");
+  }
+
 }
diff --git a/src/main/java/arb/expressions/nodes/unary/FunctionNode.java b/src/main/java/arb/expressions/nodes/unary/FunctionNode.java
@@ -160,6 +160,7 @@ public Node<D, R, F> differentiate(VariableNode<D, R, F> variable)
    */
   private Node<D, R, F> differentiateBuiltinFunction()
   {
+
     switch (functionName)
     {
     case "arcsin":
@@ -170,6 +171,10 @@ private Node<D, R, F> differentiateBuiltinFunction()
       return arg.cos();
     case "cos":
       return arg.sin().neg();
+    case "sinh":
+      return arg.cosh();
+    case "cosh":
+      return arg.sinh();
     case "exp":
       return this;
     case "log":

diff --git a/src/test/java/arb/expressions/nodes/DerivativeNodeTest.java b/src/test/java/arb/expressions/nodes/DerivativeNodeTest.java
@@ -16,6 +16,20 @@ public class DerivativeNodeTest extends
                                 TestCase
 {
 
+  public void testHyperbolicSineDerivative()
+  {
+    var f  = RealFunction.parse("∂sinh(x)/∂x");
+    var df = RealFunction.parse("cosh(x)");
+    assertEquals(df.rootNode.toString(), f.rootNode.toString());
+  }
+
+  public void testHyperbolicCosineDerivative()
+  {
+    var f  = RealFunction.parse("∂cosh(x)/∂x");
+    var df = RealFunction.parse("sinh(x)");
+    assertEquals(df.rootNode.toString(), f.rootNode.toString());
+  }
+
   public void testCotangentDerivative()
   {
     var f  = RealFunction.parse("∂cot(x)/∂x");