Fix IsApproximatelyEqual sample for negative values (#43345)

Author: cycopepe

docs/fundamentals/runtime-libraries/snippets/System/Single/Overview/csharp/comparison4.cs

@@ -11,7 +11,15 @@ public static void Main()
             one2 += .1f;
 
         Console.WriteLine($"{one1:R} = {one2:R}: {one1.Equals(one2)}");
-        Console.WriteLine($"{one1:R} is approximately equal to {one2:R}: {IsApproximatelyEqual(one1, one2, .000001f)}");
+        Console.WriteLine($"{one1:R} is approximately equal to {one2:R}: " +
+            $"{IsApproximatelyEqual(one1, one2, .000001f)}");
+        
+        float negativeOne1 = -1 * one1;
+        float negativeOne2 = -1 * one2;
+
+        Console.WriteLine($"{negativeOne1:R} = {negativeOne2:R}: {negativeOne1.Equals(negativeOne2)}");
+        Console.WriteLine($"{negativeOne1:R} is approximately equal to {negativeOne2:R}: " +
+            $"{IsApproximatelyEqual(negativeOne1, negativeOne2, .000001f)}");
     }
 
     static bool IsApproximatelyEqual(float value1, float value2, float epsilon)
@@ -31,10 +39,11 @@ static bool IsApproximatelyEqual(float value1, float value2, float epsilon)
         if (divisor.Equals(0))
             divisor = Math.Min(value1, value2);
 
-        return Math.Abs(value1 - value2) / divisor <= epsilon;
+        return Math.Abs((value1 - value2) / divisor) <= epsilon;
     }
 }
 // The example displays the following output:
 //       1 = 1.00000012: False
 //       1 is approximately equal to 1.00000012: True
+//       -1 is approximately equal to -1.00000012: True
 // </Snippet12>