Original post by NeeIam
How would you do a question like this?
Given the first term, a, the common difference, d, and the last term, l, find the sum of the following arithmetic series:
a=8, d=3, l=65
Given the first term, a, the common difference, d, and the last term, l, find the sum of the following arithmetic series:
a=8, d=3, l=65
Use the formula
Sn= n/2(a+l)
U also have to find n 65=a+(n-1)d
Original post by Xenon17
Use the formula
Sn= n/2(a+l)
U also have to find n 65=a+(n-1)d
Sn= n/2(a+l)
U also have to find n 65=a+(n-1)d
I don't understand what I'm meant to do with the 2nd formula, how to find n
Original post by NeeIam
I don't understand what I'm meant to do with the 2nd formula, how to find n
n is between the ( and-
Original post by Xenon17
n is between the ( and-
Never mind I got it thank you!
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