Arithmetic Progressions, Part 2: Adding them up
A hall has seats in the front row and more in each row behind. How many seats in all?
In this lesson you will
- Explain how the sum of an AP is found by pairing terms
- Use Sₙ = n/2 [2a + (n − 1)d] and Sₙ = n/2 (a + l)
- Find the number of terms for a given sum and interpret both roots
- Find aₙ from a formula for Sₙ
- Solve savings, instalment and arrangement problems
- seats in each row