PreCalculus
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
asked by
Sade

well, just look at the differences:
1st differences: 2 2 6 10
2nd differences: 4 4 4
Looks quadratic to me.posted by Steve
Respond to this Question
Similar Questions

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. 
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. 
precalculus
Are my answers correct if not which are right? Find the second difference for the sequence. 7, 6, 7, 10, 15, 22, …. 1 2 3 5 answer:a Find first differences for the sequence in order from a1 to a5. Determine whether or not the 
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 + 
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 + 
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? 
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? 
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, 
PreCalculus
Find P_(k+1) if P_(k)=2^(k1)/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 
math
an = 3 a_{n1}  5 a_{n2}  4 a_{n3} and a_4 = 42, a_5 = 147, and a_6 = 219. Find a_1, a_2, and a_3.