Finding the Term Number Using Nth term Formula of Arithmetic Sequences
Finding the Term Number Using Nth term Formula of Arithmetic Sequences
In previous lesson we learn to find the total number of terms of an Arithmetic Progression. I hope you are good in finding total number of terms of an AP too.
Now in this lesson we are going to learn “how to find the term number (n) of an Arithmetic Progression”. To find the term number we need to apply the nth term formula or general term of arithmetic sequence in various ways depending upon the situation.
So let’s begin our lesson, hope you keep the pen and notebook with you.
So how was it?
In this problem we were given the 3^{rd} term and 9^{th} term of Arithmetic Progression and we need to find that which term of the AP is Zero (0).
Steps

First we need to find the first term & Last term of Arithmetic progression.

Apply the nth term formula of AP in 3^{rd} term using n=3 you will get a relation.

Apply the nth term formula of AP in 9^{th} term using n =9, you will get another relation use the information got on first second step.

You will now found the first term and common difference of arithmetic progression,

Apply the nth term formula for zero, you don’t know n = ?. Use first term, common difference and nth term = 0 , you will get the value of term number (n).

N is the required term number.
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