20^{text {th }} term of sequence defined by a_{n}=(n-1)(2-n)(3+n) ?

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8. Sequences and Series

easy

What is the $20^{\text {th }}$ term of the sequence defined by

$a_{n}=(n-1)(2-n)(3+n) ?$

A

$-7866$

B

$-7866$

C

$-7866$

D

$-7866$

Solution

Putting $n=20,$ we obtain

$a_{20} =(20-1)(2-20)(3+20) $

$=19 \times(-18) \times(23)=-7866$

Standard 11

Mathematics

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