Question

For a finite sequence of nonzero numbers, the number of variations in sign is defined as the number of pairs of consecutive terms of the sequence for which the product of the two consecutive terms is negative. What is the number of variations in sign for the sequence 1, –3, 2, 5, –4, –6 ? One

Answer 1

Answer: the number of variations in sign = 3

Explanation:

Let the finite sequence 1, –3, 2, 5, –4, –6 , the only pairs of consecutive terms for which the product of the two consecutive terms is negative are :

{1, –3} ; {–3, 2}; {5, –4} then

the number of variations in sign = 3