Find the sum of first 25 terms of an ap whose n^th term is 1-4n
Answers
Answered by
2
Answer:
No. of terms of AP= 25
1st term= 1-4(1)
= -3
2nd term= 1-4(2)
= 1-8
= -7
25th term= 1-4(25)
= 1-100
= 99
AP= -3, -7,.......,99
a=-3
d=-3-(-7)
= -3+7
= 4
l= 99
Sn=n÷2(a+l)
=25÷2(-3+99)
=25÷2(96)
=25×48
=1200
Hope so this helps you.....
Answered by
2
Answer:
Step-by-step explanation:
Similar questions