Is the sequence 3, 12, 36, ... a geometric sequence? explain. type your answer below.

In a geometric sequence you get the (n+1) 'th term by multiplying the n'th term by the common ratio r.

To test if 3,12,36 ... are the terms of a geometric sequence we calculate the common ratio for 3 and 12, and 12 and 36. Thus:

r = 12/3 = 4 and r = 36/12 = 3

Since 4 is not equal to 3 there is not a constant common ratio and hence this is not a geometric sequence.