Is the sequence 2, 1, 1/2, 1/ a)arithmetic b) geometric c) both d)neither

The given sequence is a geometric sequence. The property of geometric sequence is that each term is multiplied by a specific number known as "common ratio" to get the next term. In this case the common ratio is 1/2.
2 x 1/2 = 1
1 x 1/2 = 1/2
1/2 x 1/2 = 1/4 
and so on..

Idon't know that language