Question

Write the nth term of the A.P. 7, 4, 1, –2 ........

Answer 1

hope it will help you......

Answer 2

Answer:

Required n th term is (10-3n).

Step-by-step explanation:

Given series is 7,4,1,-2,.......

This is already mentioned here that it is an AP series.

First term of this series is 7 and common difference between each term is $(4 - 7) = - 3$

Now we want to find nth term of the series.

We know, $a_n = a + (n - 1)d$

Where $a_n$is the nth term,a is the first term of the series, n is number of term and d is common difference.

So we can say that,

$a = 7$and $d = - 3$

So,required nth term of the series is $a_n = 7 + (n - 1) \times ( - 3)$

$a_n = 7 - 3(n - 1)$

$a_n = 7 - 3n + 3 = 10 - 3n$

Therefore, required n th term is (10-3n).

Some others formula of AP series,

1.General from of Ap series-

a,a+d,a+2d,a+3d,.........a+nd.

2.Sum of nth term of AP series-$s = \frac{n}{2} [2a + (n - 1)d]$

3.Sum of all terms in a finite AP with the last term as "l"-$\frac{n}{2} (a + l)$