- #1
Liquidxlax
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Homework Statement
(5^2) + (11^2) + (17^2) +...+ (18n-1)^2
a)Write the sum in sigma notation
b)Using the sigma identities solve the sum (easy to do)
Homework Equations
∑i = .5*k*(k+1) etc
The Attempt at a Solution
The problem I'm having is with the 25 and 121. I thought it was
∑ (6n-1)^2
where n goes from 1 to k,
but I noticed that this does not work for part b then.
I haven't done induction in 4 years, so unfortunately I forget.
Unless it isn't from 1 to k, but from 1 to 3k