Python/maths/sin.py
zer0-x 80f1da235b
Add sin function to maths ()
* Add sin function to /maths.

* Fix typo in /maths/sin.py

* Format sin.py to meet the new black rules.

* Some improvements.

* Fix a formating error.
2022-05-16 19:28:30 +08:00

65 lines
1.4 KiB
Python

"""
Calculate sin function.
It's not a perfect function so I am rounding the result to 10 decimal places by default.
Formula: sin(x) = x - x^3/3! + x^5/5! - x^7/7! + ...
Where: x = angle in randians.
Source:
https://www.homeschoolmath.net/teaching/sine_calculator.php
"""
from math import factorial, radians
def sin(
angle_in_degrees: float, accuracy: int = 18, rounded_values_count: int = 10
) -> float:
"""
Implement sin function.
>>> sin(0.0)
0.0
>>> sin(90.0)
1.0
>>> sin(180.0)
0.0
>>> sin(270.0)
-1.0
>>> sin(0.68)
0.0118679603
>>> sin(1.97)
0.0343762121
>>> sin(64.0)
0.8987940463
>>> sin(9999.0)
-0.9876883406
>>> sin(-689.0)
0.5150380749
>>> sin(89.7)
0.9999862922
"""
# Simplify the angle to be between 360 and -360 degrees.
angle_in_degrees = angle_in_degrees - ((angle_in_degrees // 360.0) * 360.0)
# Converting from degrees to radians
angle_in_radians = radians(angle_in_degrees)
result = angle_in_radians
a = 3
b = -1
for _ in range(accuracy):
result += (b * (angle_in_radians**a)) / factorial(a)
b = -b # One positive term and the next will be negative and so on...
a += 2 # Increased by 2 for every term.
return round(result, rounded_values_count)
if __name__ == "__main__":
__import__("doctest").testmod()