Add sine and cosine funcs

FuzzyMath/Functions/cos.cs

@@ -0,0 +1,60 @@
+using System;
+
+namespace FuzzyMath
+{
+    public static partial class Functions
+    {
+
+        /// <summary>
+        /// Calculates the cosine of a fuzzy number
+        /// </summary>
+        /// <param name="X">Fuzzy angle in radians</param>
+        public static FuzzyNumber Cos(FuzzyNumber X)
+        {
+            return FuzzyNumber.Map(X, x => Cos(x));
+        }
+
+        public static Interval Cos(Interval interval)
+        {
+            double a, b, x;
+            x = Math.Floor(interval.A / Math.PI) * Math.PI;
+
+            if (interval.Contains(x))
+            {
+                a = Math.Cos(x);
+            }
+            else
+            {
+                x += Math.PI;
+
+                if (interval.Contains(x))
+                {
+                    a = Math.Cos(x);
+                }
+                else
+                {
+                    a = Math.Cos(interval.A);
+                    b = Math.Cos(interval.B);
+
+                    return b > a ? new Interval(a, b) : new Interval(b, a);
+                }
+            }
+
+            x += Math.PI;
+
+            if (interval.Contains(x))
+            {
+                b = Math.Sin(x);
+            }
+            else
+            {
+                b = a > 0
+                    ? Math.Min(Math.Cos(interval.A), Math.Cos(interval.B))
+                    : Math.Max(Math.Cos(interval.A), Math.Cos(interval.B));
+            }
+
+            return b > a ? new Interval(a, b) : new Interval(b, a);
+        }
+
+    }
+}

FuzzyMath/Functions/sin.cs

@@ -0,0 +1,60 @@
+using System;
+
+namespace FuzzyMath
+{
+    public static partial class Functions
+    {
+
+        /// <summary>
+        /// Calculates the sine of a fuzzy number
+        /// </summary>
+        /// <param name="X">Fuzzy angle in radians</param>
+        public static FuzzyNumber Sin(FuzzyNumber X)
+        {
+            return FuzzyNumber.Map(X, x => Sin(x));
+        }
+
+        public static Interval Sin(Interval interval)
+        {
+            double a, b, x;
+            x = Math.Floor(interval.A / Math.PI) * Math.PI + Math.PI / 2;
+
+            if (interval.Contains(x))
+            {
+                a = Math.Sin(x);
+            }
+            else
+            {
+                x += Math.PI;
+
+                if (interval.Contains(x))
+                {
+                    a = Math.Sin(x);
+                }
+                else
+                {
+                    a = Math.Sin(interval.A);
+                    b = Math.Sin(interval.B);
+
+                    return b > a ? new Interval(a, b) : new Interval(b, a);
+                }
+            }
+
+            x += Math.PI;
+
+            if (interval.Contains(x))
+            {
+                b = Math.Sin(x);
+            }
+            else
+            {
+                b = a > 0
+                    ? Math.Min(Math.Sin(interval.A), Math.Sin(interval.B))
+                    : Math.Max(Math.Sin(interval.A), Math.Sin(interval.B));
+            }
+
+            return b > a ? new Interval(a, b) : new Interval(b, a);
+        }
+
+    }
+}