update area.py (TheAlgorithms#3862)

add method "area_ellipse"
- Calculate the area of a ellipse

Co-authored-by: 201502029 <[email protected]>

Author: Suyeonkkk

Diff for: maths/area.py

@@ -186,6 +186,32 @@ def area_circle(radius: float) -> float:
     return pi * radius ** 2
 
 
+def area_ellipse(radius_x: float, radius_y: float) -> float:
+    """
+    Calculate the area of a ellipse
+
+    >>> area_ellipse(10, 10)
+    314.1592653589793
+    >>> area_ellipse(10, 20)
+    628.3185307179587
+    >>> area_ellipse(-10, 20)
+    Traceback (most recent call last):
+        ...
+    ValueError: area_ellipse() only accepts non-negative values
+    >>> area_ellipse(10, -20)
+    Traceback (most recent call last):
+        ...
+    ValueError: area_ellipse() only accepts non-negative values
+    >>> area_ellipse(-10, -20)
+    Traceback (most recent call last):
+        ...
+    ValueError: area_ellipse() only accepts non-negative values
+    """
+    if radius_x < 0 or radius_y < 0:
+        raise ValueError("area_ellipse() only accepts non-negative values")
+    return pi * radius_x * radius_y
+
+
 def area_rhombus(diagonal_1: float, diagonal_2: float) -> float:
     """
     Calculate the area of a rhombus