In the context of functions, the input is often referred to as the independent variable because it can be chosen arbitrarily from the domain. Conversely, the output is called the dependent variable because its value depends on the value of the independent variable. For instance, if the price of oranges is $2.50 per pound, the total cost is determined by the product of the unit price and the weight in pounds.
As shown, the total cost of oranges depends on how many pounds of fruit are purchased. Therefore, the cost of oranges y is the dependentvariable and the number of pounds purchased x is the independentvariable.