Find the sum of the first twelve terms of the arithmetic progression, in which a1 = -5, d = 3.
| August 14, 2021 | education
Given:
a1 = -5
d = 3
n = 12
Find: S12.
Solution:
To find the sum of the arithmetic progression of the first 12 terms, we use the formula Sn = (2 * a1 + d (n – 1)) * n / 2.
S12 = (2 * (-5) + 3 (12 – 1)) * 12/2 = (-10 + 33) * 12/2 = 138.
Answer: S12 = 138.
One of the components of a person's success in our time is receiving modern high-quality education, mastering the knowledge, skills and abilities necessary for life in society. A person today needs to study almost all his life, mastering everything new and new, acquiring the necessary professional qualities.
