This week in Math 10, I have chosen to talk about domain and range.

Domain and range are which x and y coordinates respectively on a graph are represented by a line or points. Here is an example of two.

The domain is represented as an equation where D equals either a series of numbers or an inequality within the {} brackets. Range is the same, except with R instead of D. The graphs to the left, while they look like they cover the same data, are actually entirely different, as they are different data types; from left to right, continuous and discrete. Continuous data can have decimal numbers, while discrete data can only consist of integers, and is typically used for counting values.

The domain and range start with the smallest values, then continue to the largest. With continuous data, open and closed circles represent whether the inequality is a “less than” (<) or “less than or equal to” (≤) value.

With curved lines, it can be difficult to determine certain domains and ranges, like in this graph.

With this graph, you can simply point the furthest parts of the line as part of the domain or range, as if you were trying to “pinch” the line and it was entirely static. In the graph to the left, these are represented by the green dots.