Define variable in a mathematical model.

A variable in a mathematical model is a symbol that represents a quantity that can change.

In mathematical modelling, variables are used to represent quantities that can change, such as time, distance, temperature, or population size. These variables can be either independent or dependent. Independent variables are those that are not affected by other variables in the model, while dependent variables are those that are affected by other variables.

For example, in a simple linear equation y = mx + c, y is the dependent variable and x is the independent variable. The value of y depends on the value of x, which can be changed. In this equation, m and c are constants, which means they do not change.

Variables can also be classified as discrete or continuous. Discrete variables are those that can only take on certain values, such as the number of students in a class or the number of cars in a parking lot. Continuous variables, on the other hand, can take on any value within a certain range, such as temperature or time.

In mathematical modelling, it is important to clearly define the variables used in the model and their relationships to each other. This allows for accurate predictions and analysis of the system being modelled.