Question

Find the sum of
of first 30 terms where
An=4n+6n^2
An=3n+6

Answer 1

Step-by-step explanation:

An=3n+6, n=30,

put n=1

A1=3+6

=9 so, a=9

similarly a2=12

common difference=3

Sn=n/2[2a+(n-1)d]

=30/2[2×9+(30-1)×3]

=15[30+(29×3)

=15[30+87]

=15(117)

=1755 is a correct answer