find the common difference and sum of an AP whose an=7n-1
Answers
Answered by
3
given
an = 7n-1
a1 = 7*1 -1 = 7-1= 6
a2 = 7*2 -1 =14 -1 =13
a3 =7*3 -1 = 21-1 =20
common difference = d= a2 -a1
d= 13 -6 =7
first term = a= a1 = 6
sum of n terms =sn = n/2 [a+an]
=n/2 [6+7n-1]
sn=n/2[7n+5]
an = 7n-1
a1 = 7*1 -1 = 7-1= 6
a2 = 7*2 -1 =14 -1 =13
a3 =7*3 -1 = 21-1 =20
common difference = d= a2 -a1
d= 13 -6 =7
first term = a= a1 = 6
sum of n terms =sn = n/2 [a+an]
=n/2 [6+7n-1]
sn=n/2[7n+5]
viks5047:
thnx bro
welcome
Similar questions