diff --git a/classwork12.py b/classwork12.py
new file mode 100644
index 0000000..da1331b
--- /dev/null
+++ b/classwork12.py
@@ -0,0 +1,64 @@
+from math import factorial
+# Завдання 16.16(а, б)
+
+def task_a(k, x, eps):
+    assert k >= 0, "Число k повинно бути невід'ємним"
+    for d in range(k+1):
+        yield (-1)**d * x**(2*d+1)/factorial(2*d+1)
+
+    k = 0
+    s = 0
+    y = 1
+    while abs(y) >= eps:
+        y = (-1)**k * x**(2*k+1)/factorial(2*k+1)
+        s += y
+        k += 1
+    yield f'Sum = {s}'
+
+def task_b(k, x, eps):
+    assert k >= 0, "Число k повинно бути невід'ємним"
+    for d in range(k+1):
+        yield x**(2*d)/factorial(2*d)
+
+    k = 0
+    s = 0
+    y = 1
+    while abs(y) >= eps:
+        y = x**(2*k)/factorial(2*k)
+        s += y
+        k += 1
+    yield f'Sum = {s}'
+
+# Завдання 16.17(а)
+
+def log(x, eps):
+    assert abs(x) < 1, '|x| < 1'
+    y = 1
+    k = 1
+    while abs(y)>0:
+        y = (-1)**(k+1)*x**k/k
+        k += 1
+        yield y
+
+    k = 1
+    ln = 0
+    y = 1
+    while abs(y) >= eps:
+        y = (-1)**(k+1)*x**k/k
+        ln += y
+        k += 1
+
+    yield f'log({1+x}) = {ln}'
+
+if __name__ == '__main__':
+    seq = task_a(10, 10, 0.001)
+    for x in seq:
+        print(x)
+
+    seq = task_b(20, 5, 0.0001)
+    for x in seq:
+        print(x)
+
+    ln = log(0.5, 0.00001)
+    for x in ln:
+        print(x)
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