In this lesson on increasing and decreasing intervals, the concept of what it means for a function to be increasing or decreasing is explained, with a focus on supply and demand functions. The difference between strictly increasing and increasing, as well as strictly decreasing and decreasing, is also discussed. The lesson then moves on to discuss how to determine whether a function is increasing or decreasing algebraically, with examples given for linear, quadratic, exponential, and logistic functions. Finally, it is explained that the vertex of a quadratic function determines whether it is increasing or decreasing.
Understand what the terms increasing and decreasing mean with regards to a relationship. In particular, be clear on how demand and supply relationships work (i.e. are they increasing or decreasing, strictly or over only parts of the domain).
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