Math 1 · Unit 9 · Lesson 5 · part 1 of 5
The Words We Use
The vocabulary for this lesson, in one place.
Words we use
| Word | Plain English | What you do |
|---|---|---|
| Arithmetic sequence | A list that adds the same amount each time. The line family as a list. | Equal differences. Rule: start + d(n − 1). |
| Geometric sequence | A list that multiplies by the same number each time. The exponential family as a list. | Equal ratios. Rule: start · rn − 1. |
| Common difference, common ratio | d, the amount added; r, the number multiplied. | Subtract to find d; divide to find r. |
| Explicit rule, recursive rule | Any term from n; the next term from the one before. | Explicit for a far term; recursive to see how the list moves. |
| Model | A rule that stands in for a real situation. | Say what n counts and where the counting starts. |
| Zeroth term | The value one step before the first term. | Sometimes it has a real meaning: a plain pizza. |