Question

Find the nature and 30 th term of the sequence whose sum to n terms is 5n²+2n​

Answer 1

Answer:

a1=5(1)^2+2(1)=7

a2+a1=5(2)^2+2(2)

=24

a2=24-7=17

d=a2-a1

=17-7=10

s3=5*9+6=45+6=51

a3=51-17-7

=27

7,17,27 AP

a30=7+29*10

=297