Question

Question in the comment below.

Answer 1

\[\sum_{i=1}^{20} (i-1)^2\]

Answer 2

how do i simplify this using rules of summation

Answer 3

Did you try writing out the terms?

Answer 4

I could do that however im assuming there is a way of simplifying this expression without having to write out 20 terms.

Answer 5

First you could distribute the (i-1)^2

Answer 6

i-2*i-2

Answer 7

Then the laws of summation say the sum of a term plus or minus another term is equivalent to the sum of the first term plus the sum of the second term and so on.

Answer 8

Why i didnt think of that idk. Thanks