The sum of the first 7 term of an AP is 49 and the sum of it's first 17 terms is 289. Find the sum of it's first n terms.
adityasingh29:
you said me you are never tell lie with me
Mmmm
then yy u tell lie
When
???
you think own and tell me
What
ok I am going to tell you
Say??????
look msgs of saisagar6129
Answers
Answered by
14
S7=7/2(2a+6d)
49=7a+21d
7=a+3d...........(1)
Now, s17=17/2(2a+16d)
289=17a+136d
17=a+8d..................2
From1and2
5d=10
D=2
Put din 1
A=1
Sum of nth term =n/2(2+n-1)
=n2+n/2
Hope this helps you
Mark as a brainliest
49=7a+21d
7=a+3d...........(1)
Now, s17=17/2(2a+16d)
289=17a+136d
17=a+8d..................2
From1and2
5d=10
D=2
Put din 1
A=1
Sum of nth term =n/2(2+n-1)
=n2+n/2
Hope this helps you
Mark as a brainliest
Hi
have you taken dinner
Yes, do u
???
yaa
What r u doing?
going to sleep
Ok
hmm
byee
Answered by
6
HAIII HERE'S UR ANSWER .
Attachments:
but why you r saying sorry
no you r not disturbing me
ok I will talk to you later
I am going to study
Similar questions