Sequences, recurrence relations and sigma notation Quiz

1. A sequence has $u_1=3$ and $u_{n+1}=u_n^2-2$. Find $u_3$.

• A. $7$
• B. $47$
• C. $5$
• D. $79$

2. Which statement is true of the sequence $u_n=5-2n$?

• A. It is increasing.
• B. It is periodic of order 2.
• C. It is decreasing.
• D. It is neither increasing nor decreasing.

3. Find $\sum_{r=1}^{10}7$.

• A. $70$
• B. $7$
• C. $17$
• D. $77$

4. $u_1=4$ and $u_{n+1}=\frac{6}{u_n}$. Find $u_{15}$.

• A. $1.5$
• B. $6$
• C. $2.5$
• D. $4$

5. How many terms, and what total, for $\sum_{r=4}^{12}5$?

• A. $9$ terms, total $45$
• B. $8$ terms, total $40$
• C. $11$ terms, total $55$
• D. $12$ terms, total $60$