What you’ll learn
Describe increasing/decreasing/constant behavior.
Key idea
Increasing and decreasing describe changes in output as input grows; a horizontal segment has constant output.
Read left to right and report changing and constant intervals separately; a straight segment need not be horizontal.
Worked example
Enter the exact value or ordered values in the format requested below.
Straight graph segments A→B→C have x horizontal,y vertical. Describe behavior on open interval 0<x<4, with output evidence.
Marked coordinates: B=(4, 0); C=(8, 0); A=(0, -4).
- Moving left to right from A to B changes output from -4 to 0, with signed per-input change 1.
- Thus the first interval 0<x<4 is increasing; the second 4<x<8 is constant because its endpoint outputs both equal 0.
Answer: increasing on 0<x<4
Quick Check
Relate the graph used in 'Describe increasing/decreasing/constant behavior' to an equation, table, transformation, or verbal description.
This table describes straight segments between its adjacent inputs: [(0, -3), (1, -1), (2, 1), (3, 3), (4, 5), (5, 5), (6, 5), (7, 5), (8, 5)]. Connect it to the changing/constant graph intervals.
Marked coordinates: B=(4, 5); C=(8, 5); A=(0, -3).