Answered

Select the arithmatic sequence from the following: Question 11 Select one: a. 1, - 1, - 3, - 5, ........... b. 1, 1/2, 1/4, 1/8, ........... c. 1, 2, 4, 8, ........... d. 1, - 2, 4, - 8, ...........



Answer :

Answer:  Choice A

1, -1, -3, -5, ...

Reason

We start at 1 and subtract 2 from each term to get the next term.

1-2 = -1

-1-2 = -3

-3-2 = -5

The nth term of this sequence is 1-2(n-1) which simplifies to -2n+3

Choices B, C, and D are not arithmetic sequences. Instead they are geometric. This is because we multiply each term by some common ratio to get the next term. Sequence B has common ratio 1/2. Sequence C has common ratio 2. Sequence D has common ratio -2. Sequences B, C, and D all start at 1.