Question

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Answer 1

\[\Large \sum_{n = 1}^{20}\normalsize 3n\]

Answer 2

Yes.

Answer 3

That looks something like playing with the minus sign.

Answer 4

3,5,7,9,11.... are odd numbers so 2n + 1 where n starts at 1.

Answer 5

and their sign will be the (n + 1) power of (-1)

Answer 6

\[\Large \sum_{n = 1}^{}\large (-1)^{n + 1}2n + 1\]Let's see if that works

Answer 7

oh, and the upper limit is 7

Answer 8

\[f(1) = 3\]

Answer 9

Yes, it works!

Answer 10

Yes sir.

Answer 11

Yes...

Answer 12

You're welcome. Phew