Finding the sum of the first n terms in a geometric sequence

**When you're done with the video,** answer a related question.

Show me the question
Consider the geometric sequence

$latex u_{1}=9k$

$latex u_{2}=k^{2}$

$latex u_{3}=k$

a) Find the possible values for $latex k$.

b) Given that $latex k>0$, find the common ratio.

c) Find the sum of the first 3 terms.

Show answer

Answer:a) $latex k=\pm 3$

b) $latex r=\frac{1}{3}$

c) $latex S_{3}=39$

What? Why?

Next up:
Infinite geometric series