please solve this question fast
Attachments:
Answers
Answered by
0
put n equal to 1 to get a
a = 3/2 + 13/2 = 15/2
to get d subtract sum of two no by putting n equal to 2
and subtract it by a
you get d
25th term eqaul to a + 24d
a = 3/2 + 13/2 = 15/2
to get d subtract sum of two no by putting n equal to 2
and subtract it by a
you get d
25th term eqaul to a + 24d
Answered by
0
Hi ,
Sn = 3n²/2 + 13n/2
A25 = S25 - S24
= [ 3×25²/2 + 13×25/2 ] - [ 3× 24²/2 + 13× 24 /2 ]
= [ 3/2 ( 25² - 24² ) ] + 13/2 [ 25 - 24 ]
= [ 3/2 ( 25 + 24 ) ( 25 - 24 ) ] + 13/2
= [ 3/2 × 49 × 1 ] + 13/2
= 1/2 ( 147 + 13 )
= 1/2 ( 160 )
= 80
I hope this helps you.
:)
Sn = 3n²/2 + 13n/2
A25 = S25 - S24
= [ 3×25²/2 + 13×25/2 ] - [ 3× 24²/2 + 13× 24 /2 ]
= [ 3/2 ( 25² - 24² ) ] + 13/2 [ 25 - 24 ]
= [ 3/2 ( 25 + 24 ) ( 25 - 24 ) ] + 13/2
= [ 3/2 × 49 × 1 ] + 13/2
= 1/2 ( 147 + 13 )
= 1/2 ( 160 )
= 80
I hope this helps you.
:)
Similar questions