Introduction to sequences

1003085006

Level: 
A
A sequence \( \left(a_n\right)_{n=1}^{\infty} \) is defined by the recursive formula \( a_1=1\text{, }a_2=2;\ a_{n+2} = \frac12\left(a_{n+1}+a_n\right)\text{, }n\in\mathbb{N} \). What are its first five terms?
\( 1 \), \( 2 \), \( \frac32 \), \( \frac74 \), \( \frac{13}8 \)
\( 1 \), \( 2 \), \( \frac32 \), \( \frac47 \), \( \frac8{13} \)
\( 1 \), \( 2 \), \( 3 \), \( 7 \), \( 13 \)
\( 1 \), \( 2 \), \( \frac23 \), \( \frac47 \), \( \frac{13}8 \)

1003085005

Level: 
A
A sequence \( \left( a_n \right)_{n=1}^{\infty} \) is defined by the recursive formula \( a_1=1;\ a_{n+1}=\frac1{1+a_n}\text{, }n\in\mathbb{N} \). What are its first five terms?
\( 1 \), \( \frac12 \), \( \frac23 \), \( \frac35 \), \( \frac58 \)
\( 1 \), \( \frac12 \), \( \frac23 \), \( \frac34 \), \( \frac58 \)
\( 1 \), \( 2 \), \( \frac32 \), \( \frac53 \), \( \frac85 \)
\( 1 \), \( \frac12 \), \( \frac32 \), \( \frac35 \), \( \frac85 \)

1003085004

Level: 
A
A sequence \( \left(a_n\right)_{n=1}^{\infty} \) is defined by the recursive formula \( a_1=1;\ a_{n+1} = 3a_n\text{, }n\in\mathbb{N} \). What are its first five terms?
\( 1 \), \( 3 \), \( 9 \), \( 27 \), \( 81 \)
\( 3 \), \( 9 \), \( 27 \), \( 81 \), \( 243 \)
\( 1 \), \( 3 \), \( 6 \), \( 12 \), \( 24 \)
\( 1 \), \( 3 \), \( 9 \), \( 30 \), \( 90 \)

1003085003

Level: 
A
We were given the sequence \( \left(\sin\left(n\cdot\frac{\pi}2\right)\right)_{n=1}^{\infty} \). What are the first five terms?
\( 1 \), \( 0 \), \( -1 \), \( 0 \), \( 1 \)
\( 1 \), \( 0 \), \( 1 \), \( 0 \), \( 1 \)
\( -1 \), \( 0 \), \( 1 \), \( 0 \), \( 1 \)
\( 0 \), \( -1 \), \( 0 \), \( 1 \), \( 0 \)

1003085002

Level: 
A
We were given the sequence \( \left(\frac{n+3}{2n}\right)_{n=1}^{\infty} \). What are its first five terms?
\( 2 \), \( \frac54 \), \( 1 \), \( \frac78 \), \( \frac45 \)
\( \frac45 \), \( \frac78 \), \( 1 \), \( \frac54 \), \( 2 \)
\( 2 \), \( \frac45 \), \( 1 \), \( \frac87 \), \( \frac54 \)
\( \frac12 \), \( \frac23 \), \( \frac34 \), \( \frac45 \), \( \frac56 \)

1003085001

Level: 
A
We were given the sequence \( \left(\frac1{3^n}\right)_{n=1}^{\infty} \). What are its first five terms?
\( \frac13 \), \( \frac19 \), \( \frac1{27} \), \( \frac1{81} \), \( \frac1{243} \)
\( 3 \), \( 9 \), \( 27 \), \( 81 \), \( 243 \)
\( 3 \), \( 6 \), \( 9 \), \( 12 \), \( 15 \)
\( \frac13 \), \( \frac16 \), \( \frac19 \), \( \frac1{12} \), \( \frac1{15} \)

1003107310

Level: 
A
We are given a sequence \( \left( a_n \right)^{\infty}_{n=1} \) defined recursively by: \( a_1=1,\ a_2=2\,;\ a_{n+2}=\frac12\left( a_{n+1}+a_n\right),\ n\in\mathbb{N} \). Find the sum of the first four terms of this sequence.
\( \frac{25}4 \)
\( \frac{63}8 \)
\( \frac{13}4 \)
\( \frac4{25} \)