Question

Determine the AP whose sum to n terms is n(3n-4). Find the 17th term.

Answer 1

The sum to n terms is n(3n-4)

That is, 3n^2-4n

We know an equation that " if sum of n terms of an AP Sn=an^2+bn then it's first term t1 = a+b and common difference is 2a

Then here, first term is 3+4=7

And common difference is 2×3=6

Here we want to find the 17 th term t17= 7+(17-1)× 6

=103

Then the 17 th term is 103

I hope it helps you