Difference Between Variable and Parameter
Many people get confused when differentiating between a variable and parameter. Although these two terms have a number of similarities, they are also some key differences between them. Both variables and parameters are commonly used in the field of algebra, mathematics and engineering. Variables and parameters are used often to solve complex engineering problems.
Essentially, a variable can be any number that is dependent on another entity. If the value of that entity changes, the variable will also increase or decrease. Parameter on the other hand, acts a bridge between two or more variables to form a meaningful relationship. From physics to mathematics, engineering to statistical analysis, variables and parameters help us relate equations and quantities. The main difference between these two terms is that while variables keep changing, the parameter remains constant.
There are two types of variables including continuous variables and discrete variables. Mathematical and engineering problems can be solved easily be identifying and categorizing the variables in any given equation.
Instructions

1
Variable
A variable is a number of a quantity that changes with change in entity it is related to.
Consider a sample of a car moving on a road. The speed of the car can be calculated by using the formula given below.
S = D/T
Where S is the speed of the car
D is the distance covered
And T is the time taken to cover that distance
Now, in the equation above, distance and time are constants whereas speed or S is the variable. Any change recorded in the distance or time will result in a change in the speed variable. If the car covered 20 meters in 60 seconds then the speed of the car will be 20/60, which is equal to 0.33 m/sec. However, if the distance is increased to 30 meters in 60 seconds then the speed of the vehicle will be increased to 30/60 or 0.5 m/sec, showing the speed is a variable quantity, directly related to the distance and time.
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2
Parameter:
Parameter is an entity that acts as a bridge between two or more variables in any given equation.
Parameters may have different dimension than variables. In the equation given below, x and y are the variables.
X2 + y2 = 1
Solving the above equation gives,
X = cos (w)
Y = sin (w)
The values of parameter can be substituted in the equations above to find the solution.
Image courtesy: euler.renegrothmann.de