sum_of_geometric_progression (TheAlgorithms#2168)

* Add files via upload

* Rename sum_of_Geometric_Progression.py to sum_of_geometric_progression.py

* Update sum_of_geometric_progression.py

* Update maths/sum_of_geometric_progression.py

Co-authored-by: Christian Clauss <cclauss@me.com>

* Update maths/sum_of_geometric_progression.py

Co-authored-by: Christian Clauss <cclauss@me.com>

* Update maths/sum_of_geometric_progression.py

Co-authored-by: Christian Clauss <cclauss@me.com>

* Update sum_of_geometric_progression.py

* Update sum_of_geometric_progression.py

* Type hints and test for zeros and negative numbers

* Update sum_of_geometric_progression.py

Co-authored-by: Christian Clauss <cclauss@me.com>

Author: AxSmasher44

maths/sum_of_geometric_progression.py

@@ -0,0 +1,28 @@
+def sum_of_geometric_progression(
+    first_term: int, common_ratio: int, num_of_terms: int
+) -> float:
+    """"
+    Return the sum of n terms in a geometric progression.
+    >>> sum_of_geometric_progression(1, 2, 10)
+    1023.0
+    >>> sum_of_geometric_progression(1, 10, 5)
+    11111.0
+    >>> sum_of_geometric_progression(0, 2, 10)
+    0.0
+    >>> sum_of_geometric_progression(1, 0, 10)
+    1.0
+    >>> sum_of_geometric_progression(1, 2, 0)
+    -0.0
+    >>> sum_of_geometric_progression(-1, 2, 10)
+    -1023.0
+    >>> sum_of_geometric_progression(1, -2, 10)
+    -341.0
+    >>> sum_of_geometric_progression(1, 2, -10)
+    -0.9990234375
+    """
+    if common_ratio == 1:
+        # Formula for sum if common ratio is 1
+        return num_of_terms * first_term
+
+    # Formula for finding sum of n terms of a GeometricProgression
+    return (first_term / (1 - common_ratio)) * (1 - common_ratio ** num_of_terms)