1.11 Sum of infinite geometric sequences Quiz

1. Find the sum to infinity of $8+4+2+1+\ldots$

• A. $16$
• B. $12$
• C. $14$
• D. $32$

2. For which common ratio does the sum to infinity of a geometric series exist?

• A. $r=1.5$
• B. $r=-1$
• C. $r=-0.4$
• D. $r=1$

3. Write $0.7777\ldots$ as a fraction.

• A. $\frac{7}{10}$
• B. $\frac79$
• C. $\frac{7}{99}$
• D. $\frac{77}{100}$

4. A geometric series has $u_1=5$ and $S_\infty=20$. Find $r$.

• A. $\frac14$
• B. $\frac12$
• C. $\frac43$
• D. $\frac34$

5. A geometric series has $S_\infty=12$ and $r=\frac14$. Find $u_1$.

• A. $3$
• B. $8$
• C. $9$
• D. $48$