Question

Find an explicit formula for this sequence: 1 , -2 ,3 ,-4, 5,-6

Answer 1

https://www.chegg.com/homework-help/questions-and-answers/find-explicit-formula-sequence-1-1-3-5-7-q27571686

Answer 2

if we just drop the minus signs then we see that it can be an AP, so we have,
$general \: term = a + (n - 1)d$
where a is the first term (here 1) and d is the common difference (here 1).
But the sign changes every second time, so we need to change the above formula a little bit so to fit the requirement.
THE FORMULA is:
$generl \: term = [ \: a + (n - 1)d \: ]{[ - 1]}^{n - 1}$