True or False:

The following is a geometric sequence.

-1, 1, - 1, 1, - 1

The following is a geometric sequence.

-2, - 6, - 18, - 54

we can check if a given sequence is geometric or not by checking the terms present in it,

Let us find ratio of each term with it's previous term

if that ratio comes out same for every two consecutive terms then it is a geometric sequence, otherwise it is not geometric sequence.

Let us work on first one : given is : - 1,1,-1,1 ...

second term / first term = 1/-1 = - 1

third term / second term = - 1/1 = - 1

fourth term / third term = 1/-1 = - 1

fifth term / fourth term = - 1/1 = - 1

because that ratio is same so it is a geometric sequence.

* let us now work with second sequence.

eE

second term / first term = - 6/-2 = 3

third term / second term = - 18 / - 6 = 3

fourth term / third term = - 54 / - 18 = 3

hence this is also geometric sequence.

Answer : both are geometric sequence.