Difference between constants and variables difference between electricity kwh cost

1. Constants are usually written as a number, such as 12 or -4.23. However, some important constants can have names and unique symbols that are recognizable throughout mathematics and sciences. For instance, pi (symbolized as π) is a common constant in geometry, calculus, and other sciences. Because pi is an irrational number with a decimal expansion that continues infinitely without a repeating pattern, it cannot be fully written and is therefore simply indicated by its symbol or name.

2. Theoretically, a variable can be symbolized by anything except a constant number. Variables are most commonly written as a single letter, especially x and y. These letters can be chosen at random, and are simply placeholders for the actual value that the variable represents. In computer programming, variables are more commonly written as a phrase that refers to the purpose of the variable (such as bonusDollars or numberOfEmployees). Characteristics of Constants and Variables in Mathematical

This equation returns an infinite number of possible values for both y and z (5 and 9, 6 and 10, -1 and 3, etc.) Because of these infinite possibilities, equations with multiple variables are typically presented in a system of equations, or a set of multiple equations, to determine a minimum number of useful values. Variables can also be used in more specific types of equations, such as in statistical regression models, where the beta coefficients act as constants and the beta variables can be changed to determine the dependent variable given a certain set of real world conditions. A beta variable could be price, gross domestic product, inflation rate, or any other condition whose changes over time affect the dependent variable in question. Characteristics of Constants and Variables in Computer Programming

In this equation, totalStaff and numberOfInterns are both variables, but 5 is an unchanging constant. (For the purpose of this code, the constant 5 could refer to the number of permanent staff positions in a company – a number that would not change randomly.)

A constant can be defined in some programming languages. This is very similar to defining a variable, in which the constant is given a symbol or name that can be referred to over and over in the code. However, a constant cannot be redefined in a later piece of code; it must retain its original value. This allows the code writer to signify that the same constant (such as pi or a sales tax rate) is being used again, but the code compiler will not look for changes in the value of the constant, which can save on computation time.

2. Variables in computer programming have more uses and manifestations than in traditional mathematics and sciences. In programming, a variable can be a placeholder for any information, not just numbers. Variables can also be used to indicate strings, arrays, and other types of data. Take the following code:

In this example (generic code not specific to any programming language), the first line tells the program compiler that we are defining (or creating) a variable called ExampleVar. In the second line, we set the variable equal to the integer 3. We could also write this variation:

This is still a variable, but unlike in a mathematical equation, the variable is equal to a string of letters. Because we have defined ExampleVar as a variable and not a constant, at any point in the code ExampleVar could be redefined (although in most programming languages, the new value of the variable must stay the same type of information, like a new integer or string).

• Constants and variables have extra uses in computer programming compared to their uses in mathematics and sciences. Variables can be numbers, strings, or other information. A constant can be given a name or symbol just like a variable in most languages, but the value of the constant cannot be changed in later lines of code.