Question

If the sum of n terms of an ap is 3n2+2n find nth term

Answer 1

Answer:

6n - 1

Step-by-step explanation:

Sn = 3n²+2n

Sum of first 1 term= 3(1)²+2(1)

= 3(1)+2

= 3+2

= 5

So, a= 5

Similarly,

Sum of first 2 terms = 3(2)²+2(2)

= 3(4)+4

= 12+4

= 16

Now,

Second term = Sum of first 2 terms

- Sum of first 1 term

= 16-5

= 11

So, d= 11-5 = 6

now,

Nth term = a+(n-1)d

= 5+(n-1)6

= 5+6n-6

= 6n-1