Python/maths/sum_of_geometric_progression.py
Du Yuanchao 4d0a8f2355
Optimized recursive_bubble_sort (#2410)
* optimized recursive_bubble_sort

* Fixed doctest error due whitespace

* reduce loop times for optimization

* fixup! Format Python code with psf/black push

Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>
2020-09-10 10:31:26 +02:00

29 lines
939 B
Python

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)