Question

In an ap the sum of first n terms in n2+2n find its18th term

Answer 1

I HOPE THIS WILL HELP U

Answer 2

Answer:

Step-by-step explanation:

Use the sum of n terms of an AP: - If sum  

of n terms of  a sequence is given, then the  

term  

of the sequence can be determine by  

 

and common difference,

 

 

Step 1 to 3

Given: - In an AP, the sum of first n terms is  

.

To find: - The 18th terms,

Use the sum of n terms of an AP,

Given that the equation can be written as,

 

,     (1)

substitute the value of n = 18 in equation (1),

 

 

The sum of 18 terms of the AP is 360.