The general form of an A.P is: where a is the first term and d is a common difference. Here,
or
, or
The nth term of an A.P is given by, where a is the first term, d is a common difference and n is the number of terms.
Example
Find the 11th term of the AP: 23, 19, 15,…
Solution
Given a = 23, n = 11, d = 19 – 23 = – 4