From ae84d8c8c10b68f47df22a080979173826cd9f1a Mon Sep 17 00:00:00 2001
From: Stephen Crowley <stephencrowley214@gmail.com>
Date: Sat, 7 Dec 2024 21:31:46 -0600
Subject: [PATCH] https://github.com/crowlogic/arb4j/issues/253

---
 src/main/java/arb/expressions/nodes/Node.java      | 10 ++++++++++
 .../arb/expressions/nodes/unary/FunctionNode.java  |  5 +++++
 .../arb/expressions/nodes/DerivativeNodeTest.java  | 14 ++++++++++++++
 3 files changed, 29 insertions(+)

diff --git a/src/main/java/arb/expressions/nodes/Node.java b/src/main/java/arb/expressions/nodes/Node.java
index 3a01de648..c1d4af61a 100644
--- 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
index e539bc48f..e8ce840cd 100644
--- 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
index f9cd53e22..07e7eeafc 100644
--- 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");