fix(maths): correct coordinate subtraction in DistanceFormula.euclideanDistance (#7747)

Author: spidervirus

src/main/java/com/thealgorithms/maths/DistanceFormula.java

@@ -6,7 +6,7 @@ private DistanceFormula() {
 
     public static double euclideanDistance(double x1, double y1, double x2, double y2) {
         double dX = Math.pow(x2 - x1, 2);
-        double dY = Math.pow(y2 - x1, 2);
+        double dY = Math.pow(y2 - y1, 2);
         return Math.sqrt(dX + dY);
     }
 

src/test/java/com/thealgorithms/maths/DistanceFormulaTest.java

@@ -14,17 +14,32 @@ void euclideanTest1() {
 
     @Test
     void euclideanTest2() {
-        Assertions.assertEquals(7.0710678118654755, DistanceFormula.euclideanDistance(1, 3, 8, 0));
+        Assertions.assertEquals(7.615773105863909, DistanceFormula.euclideanDistance(1, 3, 8, 0));
     }
 
     @Test
     void euclideanTest3() {
-        Assertions.assertEquals(110.91911467371168, DistanceFormula.euclideanDistance(2.4, 9.1, 55.1, 100));
+        Assertions.assertEquals(105.07188015829927, DistanceFormula.euclideanDistance(2.4, 9.1, 55.1, 100));
     }
 
     @Test
     void euclideanTest4() {
-        Assertions.assertEquals(19022.067605809836, DistanceFormula.euclideanDistance(1000, 13, 20000, 84));
+        Assertions.assertEquals(19000.13265743163, DistanceFormula.euclideanDistance(1000, 13, 20000, 84));
+    }
+
+    @Test
+    void euclideanTestZeroDistance() {
+        Assertions.assertEquals(0.0, DistanceFormula.euclideanDistance(0, 0, 0, 0));
+    }
+
+    @Test
+    void euclideanTestPythagoreanTriple() {
+        Assertions.assertEquals(5.0, DistanceFormula.euclideanDistance(0, 0, 3, 4));
+    }
+
+    @Test
+    void euclideanTestNegativeCoordinates() {
+        Assertions.assertEquals(5.0, DistanceFormula.euclideanDistance(-1, -2, 2, 2));
     }
 
     @Test