Question

if an=2n^2+5 then find a3

Answer 1

Answer:

$Value \: of \: a_{3}=23$

Step-by-step explanation:

$Given \: a_{n}=2n^{2}+5$

$Now, \\Value \: of \: a_{3}\\=2\times 3^{2}+5\\=2\times 9+5\\=18+5\\=23$

Therefore,

$Value \: of \: a_{3}=23$

•••♪

Answer 2

Answer:

8n³+60n²+150n+125

Step-by-step explanation:

an=2n²+5

a= 2n²+5/n

a=2n+5

then. a³= (2n+5)³

(2n+5)(2n+5)(2n+5)

(4n²+10n+10n+25)(2n+5)

(4n²+20n+25)(2n+5)

8n³+40n²+50n+20n²+100n+125

8n³+60n²+150n+125.....