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šŸ“ˆ Increasing, Decreasing & Constant Functions

Intervals • Slope direction • Graphs of famous functions

Instructor: Rabbia Abid Khan Ā· MforMathodology

1. The big idea

Read a graph left to right. If it climbs, the function is increasing; if it falls, decreasing; if it stays level, constant. For x₁ < xā‚‚ in an interval:

Increasing: f(x₁) < f(xā‚‚)  |  Decreasing: f(x₁) > f(xā‚‚)  |  Constant: f(x₁) = f(xā‚‚)
Slope > 0
f′(x) > 0 → increasing ↗
Slope < 0
f′(x) < 0 → decreasing ā†˜
Slope = 0
f′(x) = 0 → constant →
šŸ”— Link to derivatives: f′(x) is the slope of the tangent line. So the sign of f′ tells the direction of the graph. Where f′ changes sign, the graph turns around (a local max or min).

2. Explore famous functions

Pick a function, then drag the slider. The tangent line shows the slope; the graph is coloured 🟢 increasing, šŸ”“ decreasing, ⚪ constant. The coloured strip under the x-axis is the interval map.

3. šŸŽÆ Practice quiz (24 MCQs)

šŸ“ŗ Learn more

šŸ“ŗ To learn any topic in detail, watch our free lectures and read the notes on our website mformathodology.com and on our YouTube channel @MforMATHODOLOGY.

Instructor: Rabbia Abid Khan Ā· MforMathodology