- #1
Nubcake
- 35
- 0
Calculate 5 [itex]\Sigma[/itex] r=0 r(r+1)
(Sorry I don't know how to do the proper notation online)
How do you calculate the sum for this since the common difference is changing?
I tried to write them out separately so the sum of r x sum of r+1 but I don't know how you put that in the sum formula.
Sn = n/2[2a + (n-1)d]
Sn = n/2[a + L]
(Sorry I don't know how to do the proper notation online)
How do you calculate the sum for this since the common difference is changing?
I tried to write them out separately so the sum of r x sum of r+1 but I don't know how you put that in the sum formula.
Sn = n/2[2a + (n-1)d]
Sn = n/2[a + L]