Broke some menu items up into interfaces. Happy with this so far.

Base/Abstract/IDerivable.cs

@@ -0,0 +1,8 @@
+using Graphing.Graphables;
+
+namespace Graphing.Abstract;
+
+public interface IDerivable
+{
+    public Equation Derive();
+}

Base/Abstract/IIntegrable.cs

@@ -0,0 +1,8 @@
+using Graphing.Graphables;
+
+namespace Graphing.Abstract;
+
+public interface IIntegrable
+{
+    public IntegralEquation Integrate();
+}

Base/Forms/GraphForm.cs

@@ -1,4 +1,5 @@
-using Graphing.Graphables;
+using Graphing.Abstract;
+using Graphing.Graphables;
 using Graphing.Parts;
 using System;
 using System.Collections.Generic;
@@ -362,22 +363,24 @@ public partial class GraphForm : Form
             colorItem.Click += (o, e) => GraphColorPickerButton_Click(able);
             MenuColors.DropDownItems.Add(colorItem);
 
-            if (able is Equation equ)
+            if (able is IDerivable derivable)
             {
                 ToolStripMenuItem derivativeItem = new()
                 {
                     ForeColor = able.Color,
                     Text = able.Name
                 };
-                derivativeItem.Click += (o, e) => EquationComputeDerivative_Click(equ);
+                derivativeItem.Click += (o, e) => Graph(derivable.Derive());
                 MenuEquationsDerivative.DropDownItems.Add(derivativeItem);
-
+            }
+            if (able is IIntegrable integrable)
+            {
                 ToolStripMenuItem integralItem = new()
                 {
                     ForeColor = able.Color,
                     Text = able.Name
                 };
-                integralItem.Click += (o, e) => EquationComputeIntegral_Click(equ);
+                integralItem.Click += (o, e) => Graph(integrable.Integrate());
                 MenuEquationsIntegral.DropDownItems.Add(integralItem);
             }
         }
@@ -409,30 +412,6 @@ public partial class GraphForm : Form
         Size = initialWindowSize;
         WindowState = FormWindowState.Normal;
     }
-    private void EquationComputeDerivative_Click(Equation equation)
-    {
-        EquationDelegate equ = equation.GetDelegate();
-        string oldName = equation.Name, newName;
-        if (oldName.StartsWith("Derivative of ")) newName = "Second Derivative of " + oldName[14..];
-        else if (oldName.StartsWith("Second Derivative of ")) newName = "Third Derivative of " + oldName[21..];
-        else newName = "Derivative of " + oldName;
-        // TODO: anti-integrate (maybe).
-
-        Graph(new Equation(DerivativeAtPoint(equ))
-        {
-            Name = newName
-        });
-
-        static EquationDelegate DerivativeAtPoint(EquationDelegate e)
-        {
-            const double step = 1e-3;
-            return x => (e(x + step) - e(x)) / step;
-        }
-    }
-    private void EquationComputeIntegral_Click(Equation equation)
-    {
-        Graph(equation.Integrate());
-    }
 
     private void MenuMiscCaches_Click(object? sender, EventArgs e)
     {

Base/Graphables/Equation.cs

@@ -1,11 +1,12 @@
-using Graphing.Forms;
+using Graphing.Abstract;
+using Graphing.Forms;
 using Graphing.Parts;
 using System;
 using System.Collections.Generic;
 
 namespace Graphing.Graphables;
 
-public class Equation : Graphable
+public class Equation : Graphable, IIntegrable, IDerivable
 {
     private static int equationNum;
 
@@ -48,6 +49,11 @@ public class Equation : Graphable
         return lines;
     }
 
+    public Equation Derive() => new(x =>
+    {
+        const double step = 1e-3;
+        return (equ(x + step) - equ(x)) / step;
+    });
     public IntegralEquation Integrate() => new(this);
 
     public EquationDelegate GetDelegate() => equ;

Base/Graphables/IntegralEquation.cs

@@ -1,11 +1,12 @@
-using Graphing.Forms;
+using Graphing.Abstract;
+using Graphing.Forms;
 using Graphing.Parts;
 using System;
 using System.Collections.Generic;
 
 namespace Graphing.Graphables;
 
-public class IntegralEquation : Graphable
+public class IntegralEquation : Graphable, IIntegrable, IDerivable
 {
     protected readonly Equation baseEqu;
     protected readonly EquationDelegate baseEquDel;
@@ -113,11 +114,18 @@ public class IntegralEquation : Graphable
         return lines;
     }
 
-    public Equation AsEquation() => new(GetIntegralAtPoint);
+    public Equation AsEquation() => new(IntegralAtPoint)
+    {
+        Name = Name,
+        Color = Color
+    };
+
+    public Equation Derive() => (Equation)baseEqu.DeepCopy();
+    public IntegralEquation Integrate() => AsEquation().Integrate();
 
     // Standard integral method.
     // Inefficient for successive calls.
-    public double GetIntegralAtPoint(double x)
+    public double IntegralAtPoint(double x)
     {
         EquationDelegate equ = baseEqu.GetDelegate();
 

Testing/Program.cs

@@ -23,6 +23,9 @@ internal static class Program
         // Keep in mind this uses more memory than usual and can take
         // some time.
 
+        // Integrating equations is now much smoother and less intensive.
+        // Try it out!
+
         Application.Run(graph);
     }
 }