Question

write an explicit formula for sequence
The Given Sequence is..
3,-6,12,-24..

Answer 1

screwed up big, rewrinting

Answer 2

\[(-1)^{n+1}*3*n,n \in \mathbb{N} \]

Answer 3

approach: alternating + and - is achieved by (-1)^n since this is - 1 if n is odd and 1 if n is even, however, we have to start with 1, which gives -1, not the +1 that we need, so (-1)^(n+1) solves the problem., the aboslute value is just 3 times the natural numbers, so 3*n follows