Question

find the sixth term of A.P. if the sum of nth terms is given by 3n-6n^2.​

Answer 1

Step-by-step explanation:

s

n

=3n

2

+6n

s

n−1

=3(n−1)

2

+6(n−1)

s

n−1

=3(n

2

−2n+1)+6n−6

s

n−1

=3(n

2

−2n+1)+6n−6

s

n−1

=3n

2

−6n+3+6n−6

s

n−1

=3n

2

−3

t

n

=s

n

−s

n−1

t

n

=3n

2

+6n−3n

2

+3

t

n

=6n+3