# Pre-Calculus

posted by .

Find first differences for the sequence in order from a_1 to a_5. Determine whether or not the series is quadratic or not.(I used _ as a sign for a subscript)

-1, -3, -1, 5, 15

A. 2, 2, 6, 10; not quadratic

B. 2, 2, 6, 10; quadratic

C. -2, 2, 6, 10; not quadratic

D. -2, 2, 6, 10; quadratic

• Pre-Calculus -

well, just look at the differences:

1st differences: -2 2 6 10
2nd differences: 4 4 4

## Similar Questions

1. ### Algebra 2

The sequence a is defined recursively by: a_1 = 6, and a_(i+1) = a_i + 8 for all i >= 1. Then a_5 = Choose one answer. a. 38 b. 22 c. 30 d. 46 I chose a. Is that right?
2. ### MaTh

Let a_1, a_2, . . . , a_10 be an arithmetic sequence. If a_1 + a_3 + a_5 + a_7 + a_9 = 17 and a_2 + a_4 + a_6 + a_8 + a_{10} = 15, then find a_1.
3. ### Sequences

For any sequence of real numbers A = {A_1, A_2, A_3, ... }, define *A to be the sequence {A_2 - A_1, A_3 - A_2, A_4 - A_3,..}. Suppose that all of the terms of the sequence *(*A) are 1, and that A_19 = A_92 = 0. Find A_1. Help me, …
4. ### math Help plz

1.Given a geometric sequence with a_1=6 and r=2/3, write an explicit formula for a_n, the nth term of the sequence. 2.A geometric sequence has a_4=4 and a_5=7. What is a?
5. ### Algebra

Find the first 4 terms of the recursively defined sequence. a subscript 1 =9​, a subscript 2 =9​, a Subscript n+1=a Subscript n +a Subscript n-1 Are the first four terms A)9,9,18,18 B)9,9,9,27 C)9,9,81,729 D)9,9,18,27
6. ### Pre-Calculus

Find P_(k+1) if P_(k)=2^(k-1)/k! (I used _ as a sign for a subscript) A. 2^(k+1)/(k+1)! B. 2^k/(k+1)! C. 2^(k+1)/k!+1 D. 2k/k!+1 Thank you
7. ### precalculus

can you check my answers? Find the second difference for the sequence. 7, 6, 7, 10, 15, 22, …. answer: 1 Find first differences for the sequence in order from a1 to a5. Determine whether or not the series is quadratic or not. -1,
8. ### precalculus

can you check my answers? Find Pk + 1 if Pk = 7 + 13 + 19 + ...+[6(k - 1)+1] + (6k + 1) 7 + 13 + 19 + …+[6(k - 1) + 1] + (6k + 1) + [6(k + 1) + 1] 8 + 14 + 20 + …+[7(k - 1) + 1] + (7k + 1) 7 + 13 + 19 + …+(6k + 1) 7 + 13 + 19
9. ### can you check my answers precalculus

can you check my answers? Find Pk + 1 if Pk = 7 + 13 + 19 + ...+[6(k - 1)+1] + (6k + 1) 7 + 13 + 19 + …+[6(k - 1) + 1] + (6k + 1) + [6(k + 1) + 1] 8 + 14 + 20 + …+[7(k - 1) + 1] + (7k + 1) 7 + 13 + 19 + …+(6k + 1) 7 + 13 + 19
10. ### precalculus

Are my answers correct if not which are right?

More Similar Questions