Question

The sum of first n terms of an AP is given by Sn = 2n 2 3n =+ . Find the sixteenth term of the AP.

Answer 1

Hey !!
Check the attachment.
Hope it helps :)

Answer 2

hello Frnd 

Here is your answer

Given as 

$s_{n} = 2 {n}^{2} + 3n$

➡To find out we need to find first term and Common difference 

✴Let n= 1

$s_{1} = 2 ({1}^{2} ) + 3(1) \\ = 5$

We got the first term a = 5

✴Now also put n=2 

$s_{2} = 2 ({2}^{2} ) + 3(2) \\ = 14$

Since it's the sum of 2 terms 
That's why 

2nd term = S2 - a 
= 14 - 5 
= 9 

▶Now we have 
a1 = 5 and a2 = 9 

Now d = a2- a1 
d = 9 - 5 = 4 

❇Now 16th term 

$a_{16} = a + 15d$
= 5 + 15 ( 4 )
= 65



hope it helps
jerri