From b7b55f7d3575716f3eb2d3df8d02adff5a169047 Mon Sep 17 00:00:00 2001
From: Arlan Tengga <arlantengga8@gmail.com>
Date: Sun, 19 Oct 2025 12:59:28 +0700
Subject: [PATCH 1/3] feat: menambahkan algoritma cosinus

---
 math/cos.py | 56 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 56 insertions(+)
 create mode 100644 math/cos.py

diff --git a/math/cos.py b/math/cos.py
new file mode 100644
index 00000000..7e476a9f
--- /dev/null
+++ b/math/cos.py
@@ -0,0 +1,56 @@
+# Menghitung cosisnus dengan menggunakan deret taylor
+# https://en.wikipedia.org/wiki/Taylor_series#Trigonometric_functions
+import numpy as np
+
+
+def factorial(x):
+    if x < 0:
+        return ValueError("Angkanya harus bilangan real")
+    if x == 0 or x == 1:
+        return 1
+    else:
+        return x * (factorial(x - 1))
+
+
+def cosinus(sudut):
+    """
+    Cosinus adalah sebuah perbandingan dari sisi samping dan
+    miring segitiga siku-siku.
+
+    >>> cosinus(0)
+    1.0
+    >>> cosinus(30)
+    0.8660254037844386
+    >>> cosinus(45)
+    0.7071067811865475
+    >>> cosinus(60)
+    0.5000000000000001
+    >>> cosinus(90)
+    -3.3769215522516056e-15
+    """
+    result = 0.0
+    interable = 10
+    radian = sudut * np.pi / 180
+    for i in range(interable):
+        numerator = np.pow(radian, 2 * i) * np.pow(-1, i)
+        detector = factorial(2 * i)
+        result = result + (numerator / detector)
+
+    return float(result)
+
+
+def main(args=None):
+    import doctest
+
+    doctest.testmod()
+
+    # base case
+    print(cosinus(0))  # 1.0
+    print(cosinus(30))  # 0.8660254037844386
+    print(cosinus(45))  # 0.7071067811865475
+    print(cosinus(60))  # 0.5000000000000001
+    print(cosinus(90))  # -3.3769215522516056e-15
+
+
+if __name__ == "__main__":
+    main()

From 9adc67e61cf75ca4902c3ccf90656bd4b7372f36 Mon Sep 17 00:00:00 2001
From: Arlan Tengga <arlantengga8@gmail.com>
Date: Wed, 22 Oct 2025 08:26:23 +0700
Subject: [PATCH 2/3] fix: menghapus numpy

---
 math/cos.py | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/math/cos.py b/math/cos.py
index 7e476a9f..c3bb1f01 100644
--- a/math/cos.py
+++ b/math/cos.py
@@ -1,6 +1,6 @@
 # Menghitung cosisnus dengan menggunakan deret taylor
 # https://en.wikipedia.org/wiki/Taylor_series#Trigonometric_functions
-import numpy as np
+import math
 
 
 def factorial(x):
@@ -30,9 +30,9 @@ def cosinus(sudut):
     """
     result = 0.0
     interable = 10
-    radian = sudut * np.pi / 180
+    radian = sudut * math.pi / 180
     for i in range(interable):
-        numerator = np.pow(radian, 2 * i) * np.pow(-1, i)
+        numerator = math.pow(radian, 2 * i) * math.pow(-1, i)
         detector = factorial(2 * i)
         result = result + (numerator / detector)
 

From fb338154845ed758c6a48e61a9f6526c96d49e11 Mon Sep 17 00:00:00 2001
From: Arlan Tengga <arlantengga8@gmail.com>
Date: Thu, 13 Nov 2025 20:40:28 +0700
Subject: [PATCH 3/3] fix: menambahkan type hints

---
 math/cos.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/math/cos.py b/math/cos.py
index c3bb1f01..91e38c58 100644
--- a/math/cos.py
+++ b/math/cos.py
@@ -3,7 +3,7 @@
 import math
 
 
-def factorial(x):
+def factorial(x) -> int:
     if x < 0:
         return ValueError("Angkanya harus bilangan real")
     if x == 0 or x == 1:
@@ -12,7 +12,7 @@ def factorial(x):
         return x * (factorial(x - 1))
 
 
-def cosinus(sudut):
+def cosinus(sudut) -> float:
     """
     Cosinus adalah sebuah perbandingan dari sisi samping dan
     miring segitiga siku-siku.