1. - 3.5. - 7.9 according to this rule, how to express the nth number
(1-2n)
When you see the alternation of positive and negative, you should think of the special sequence of numbers to the nth power of (- 1)
(1-2n)
When you see the alternation of positive and negative, you should think of the special sequence of numbers to the nth power of (- 1)