Question

If the sum of the first m terms of an A.P is given by m^2/2+2, find the 61st term of the A.P.​

Answer 1

Step-by-step explanation:

sm=2m

2

+3m

sm−1=2(m−1)

2

+3(m−1)

=2(m

2

+1−2m)+3m−3

=2m

2

+2−4m+3m−3

=2m

2

−m−1

∴sm−sm−1=2m

2

−+3m−(2m

2

−m−1)=2m

2

+3m−2m

2

+m+1

=4m+1

General term=am=4m+1

Second term=a

2

=4(2)+1=8+1=9