Math Investigations - IV
S&S Quiz #1
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Name:____________________________
1. For each sequence given below, mark which type(s) of sequence it could be:
 Arithmetic
a. 1, 2, 6, 24,
b. 
1 1 1 7 1
, , , , ,
10 20 5 20 2
 Arithmetic
c. 3, 4, 6,12,
d.
5
5 5 10
, , , ,
12 6 3
3
 Geometric
 Geometric
 Harmonic
 Harmonic
2 pts each
 None of these
 None of these
 Arithmetic
 Geometric
 Harmonic
 None of these
 Arithmetic
 Geometric
 Harmonic
 None of these
2. Given the following sequence is arithmetic, write an explicit formula for the sequence. 3 pts
a3  65 and a11  25
Explicit Formula:
3. If the following sequence is geometric, find the next two terms, then write explicit and
recursive formulas for the sequence. 5 pts
12,3, ________,
Recursive Formula:
________
Explicit Formula:
4. If the following sequence is harmonic, find the next two terms, then write an explicit formula
for the sequence.
4 pts
1 1
, , ________,
3 2
________
Explicit Formula:
5. Write the terms of each of the following sequences. 2 pts each
5
 ( 1) n 1 
a. 

 n  1 n  2
b.
an n 1 where
c.
 an  n  5
6
7
 3 if n is even
an   2
2n if n is odd
where an  (i, j ) : i and j are whole number and i  j  n .