Concept of dependent variables in math and statistics

A dependent variable in math is a variable the value of which depends on one or more other variables. For example if we have an equation that looks like: y = 2x+ 3. Here, y is one such variable because the value of y would depend on what value is assigned to x. Such an equation is called an equation in two variables. When plotting such a relationship on a graph, the independent of the variable x is usually plotted on the x axis and the dependent-variable axis is usually the y axis. Therefore, if the relationship is like this: p = 3q + 7, then the independent of the variable q would be plotted on the x axis and the dependent of these which is p would be plotted on the y axis.

Dependent variable in an experiment can be compared to the output of the experiment. The independent of these variables is usually the input variable in any dependent random variables experiment. This definition of the dependent type of variable is by and large common throughout the world. However its application would vary a little depending on whether the experiment is statistical or is it just mathematics.
Dependent variables examples:

A medical research laboratory is studying the effect of a specific drug in treatment of cancer. Here the quantity of drug administered would be the independent-variable, and the affect the drug has on cancer would be the dependent of the variables.  This is also a statistical example of such dependent pattern variable.

The equation we saw above: y = 2x + 3 is a mathematical example. Here y is the dependent and x is the independent one. When talking of these dependent of the variables, another concept that needs to be considered is that of limited dependent variables and unlimited dependent ones.  This concept is more applicable to statistical models. There are experiments where in one independent of the variable affects more than one dependent patterns. These multiple dependent or responding variables may be limited to 2 or 4 or 10 or may be unlimited. For example if the amount of chlorine in a water supply system of a town is the responding variable, and we know that change in the chlorine amount would affect the people drinking that water, people using that water for washing clothes or utensils, the effect of such water on animals, plants, metal pipes that carry that water, etc. Therefore there are many dependent or responding variables.