Question

If the sum of first n terms of an A.P. is 3n² + n then find its common difference and n th term.


PLS ANSWER FAST

Answer 1

Answer:

Correct option is

A

2

Let S

n

be the sum of n terms of an AP with first term a and common difference d.

Since S

n

=3n

2

−n and d=6

⇒S

n

=

2

n

(2a+(n−1)d)=3n

2

−n

2

n

(2a+(n−1)6)=3n

2

−n

n(a+(n−1)3)=3n

2

−n

(a+3n−3)=3n−1

a=2

Answer 2

Answer:

refer the attachment

Step-by-step explanation:

refer this above picture