Math, asked by sakshijha3, 1 year ago

find the 15 th and n th terms of the AP 16,11,6,1,-4,-9

Answers

Answered by omprakashsamantray

heres d answer 4 u nth term is 6 and 15th term is -54

Attachments:

omprakashsamantray: i got n=6!!

omprakashsamantray: check it out

omprakashsamantray: an is -9

sivaprasath: no, a n =-9 is not given,.where,. he asked to find nth term and 15th terms only,.

omprakashsamantray: arey she has asked for the nth term and 15th term not an

sivaprasath: yes,/

sivaprasath: nth term is a n ,

omprakashsamantray: look the last term is -9 which means that an is -9

sivaprasath: NO,.IT DOESN'T MEAN THAT,.

sivaprasath: nth term means a n,.

Answered by sivaprasath

Solution:

Given:

AP: 16,11,6,1,-4,-9,...

∴ a = 16 ,

$d = a_2-a_1 = 11 - 16 = -5,$

∴ d = -5 ,

_____________________________________________________________

To find:

$a_{15} =? ,$

$a_n = ?$

_____________________________________________________________
solution

We know that,

∴ $a_n = a+(n-1)d$

so, n= 15 (1 st case),.

=> $a_{15} =a+(15-1)d$

=> $a_{15} = 16+(14)(-5)$

=> $a_{15} = 16-70$

∴ $a_{15} = -54$

_____________________________________________________________

let n = n itself (2nd case)

=> $a_n = a+(n-1) d$

=> $a_n = 16+(n-1)(-5)$

=> $a_n = 16+(n)(-5)+(-1)(-5)$

=> $a_n = 16-5n+5$

∴ $a_n = 21-5n$

_____________________________________________________________

Hope it Helps !!

sivaprasath: Mark as Brainliest

omprakashsamantray: here she has asked for nth term not an

Previous Question

Next Question