Question

The sum of 'n' terms of an AP is given by the expression 3n²-2n. Find the AP and find its 21st term.​

Answer 1

Answer:

here is the ans

Step-by-step explanation:

the AP is 3×1-2×1, 3×4-2×2, 3×9-2×3 ..

=1,8,15,..

the 21th term of AP is,

( 3×(21×21))-2×21

=(3×441)-42

=1323-42

=1281

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