# How do you write the first five terms of the geometric sequence a_1=5, r=-1/10?

Apr 21, 2017

$\text{ "5" "-0.5," "0.05," "-0.005," } 0.0005$

#### Explanation:

The General term is ${T}_{n} = a {n}^{n - 1}$

Option 1.: Let $n = 1 , 2 , 3 , 4 , 5$ and calculate each term.

Option 2: Multiply one term by $- \frac{1}{10}$ to get the next.
This seems the easier option.

$5 \times - \frac{1}{10} = - 0.5$

$- 0.5 \times - \frac{1}{10} = 0.05$ and so on,

This gives: $\text{ "5" "-0.5," "0.05," "-0.005," } 0.0005$

Notice the sign changes each time.