In any sequence of n nonzero numbers, a pair of consecutive terms with opposite signs represents a sign change. For example, the sequence –2, 3, –4, 5 has three sign changes. Does the sequence of nonzero numbers $$s_1$$, $$s_2$$, $$s_3$$, - , $$s_n$$ have an even number of sign changes?
1.$$s_k= (-1)^{k}$$ for all positive integers k from 1 to n.
2.n is odd.