Step-3

Title: Arithmetic progression

Grade: 9-a Lesson: S3-L7

Explanation: Hello Students, time to practice and review the steps for the problem.

Lesson Steps

Steps Problem Solution

1

Let \$a_n\$ be the arithmetic progression.If \$a_1 = 3 , a_2 = 12\$.

Determine \$a_35\$

2

Difference between two consective numbers

\$ d = a_n - a_(n-1) \$

3

Substitute the \$a_1 , a_2 \$

\$ d = a_2 - a_1 \$

3

Substitute the \$a_1 = 3 , a_2 = 12\$

\$d = 12 - 3 \$ = 9

5

Formula for \$n_(th)\$ number of series

\$ a_n = a_1 + (n-1)d \$

6

Substitute d = 9 , n = 35 we get

\$ a_35 = 3 + (35-1)9 \$

7

Simplify

\$ a_11 = 3 + (34)9 \$

\$ a_11 = 3 + 306 \$

8

Answer

A ⇒ \$a_11 = 309\$


Copyright © 2020-2022 saibook.us Contact: info@saibook.us Version: 1.5 Built: 20-February-2023 08:10 PM EST