Question

formula for finding n (AP)​

Answer 1

Answer:

$S_{n}=\dfrac{n}{2}(a+a_{n})$

Step-by-step explanation:

The A.P is the series in which the difference of the terms are common such as 1,3,5,7...... like this. Such term we would call as common difference or

d=$a_{2}-a_{1}$

$a_{2}$ is the second term

$a_{1}$ is the first term of AP

So we can determine the last term of A.P by the formula

$a_{n}=a+(n-1)d$ where n is the total number of terms in an A.P

And the sum of the A.P is given by the formula

$S_{n}=\dfrac{n}{2}(a+a_{n})$