Math 1 · Unit 2 · Lesson 6 · 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 |
|---|---|---|
| Average rate of change | How much the output changes for each step of the input, over a stretch. The change in the output divided by the change in the input. | Pick two points, subtract the outputs for the top, subtract the inputs for the bottom, divide. |
| Interval | The stretch of inputs from one value to another, like from x = 1 to x = 5. | Always say which interval you used. A curve can have a different rate on a different interval. |
| Change in the output | The top of the fraction (the numerator): second output minus first output. | Keep the order. A negative top means the output went down. |
| Change in the input | The bottom of the fraction (the denominator): second input minus first input, same order. | Usually positive when you read left to right. |
| Positive rate, negative rate | Positive: climbing. Negative: falling. Zero: flat. | Say the sign in story words: growing 2 inches per week, losing 30 gallons per minute. |
| Per | For each one. Miles per hour means miles for each hour. | Every rate is a per: output units per one input unit. |