Definition of differential equation

In summary, a differential equation is an equation that contains derivatives of one or more unknown functions with respect to one or more independent variables. The independent variable is the variable with respect to which the derivatives are taken, while the dependent variables are the functions whose derivatives are involved in the equation. In the case of an equation like $\frac{dy}{dx}$, the independent variable is $x$.
  • #1
find_the_fun
148
0
My textbook defines differential equation as

an equation containing the derivatives of one or more unknown functions(or dependent variables), with respect to one or more independent variables.

Could someone explain what is meant by the part in parenthesis "dependent variables"? I don't see the difference.
 
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  • #2
find_the_fun said:
My textbook defines differential equation as
Could someone explain what is meant by the part in parenthesis "dependent variables"? I don't see the difference.

When a differential equation involves one or more derivatives with respect to a particular variable, that variable is called the independent variable.

A variable is called dependent if a derivative of that variable occurs.

When $y = y(x)$ is an unknown function in respect to $x$, $y$ is a dependent variable and $x$ an independent variable.
 
  • #3
mathmari said:
When a differential equation involves one or more derivatives with respect to a particular variable, that variable is called the independent variable.
So in the case \(\displaystyle \frac{dy}{dx}\) the\(\displaystyle x\) is referred to as the independent variable?
 
  • #4
find_the_fun said:
So in the case \(\displaystyle \frac{dy}{dx}\) the\(\displaystyle x\) is referred to as the independent variable?

Yes, that's right!
 
  • #5


The term "dependent variables" refers to the functions in the differential equation that are dependent on the independent variables. In other words, the values of the dependent variables are determined by the values of the independent variables and their derivatives. This is in contrast to the independent variables, which are chosen or specified by the experimenter or problem at hand. In a differential equation, the relationship between the dependent and independent variables is described by the derivatives, which represent the rate of change of the dependent variables with respect to the independent variables. The inclusion of the term "dependent variables" in the definition highlights the fact that these variables are not independent, but rather their values are determined by the values of the independent variables and their derivatives.
 

FAQ: Definition of differential equation

What is a differential equation?

A differential equation is a mathematical equation that relates an unknown function to its derivatives. It describes the relationship between a function and its rate of change, and is commonly used in fields such as physics, engineering, and economics to model various natural phenomena.

What are the types of differential equations?

There are several types of differential equations, including ordinary differential equations (ODEs) and partial differential equations (PDEs). ODEs involve a single independent variable, while PDEs involve multiple independent variables. Other types include linear and nonlinear differential equations, as well as first-order and higher-order differential equations.

What is the order of a differential equation?

The order of a differential equation refers to the highest derivative present in the equation. For example, a first-order differential equation has only the first derivative, while a second-order differential equation has the second derivative as its highest derivative.

How are differential equations solved?

The method for solving a differential equation depends on its type and order. Some common techniques include separation of variables, substitution, and the use of integrating factors. For more complex equations, numerical methods may be used to approximate a solution.

What are some real-world applications of differential equations?

Differential equations are used in a wide range of fields and real-world applications. In physics, they are used to model the motion of objects and the behavior of physical systems. In engineering, they are used to design and analyze systems such as electrical circuits and chemical reactions. In economics, they are used to model population growth and market dynamics. They are also used in other areas such as biology, medicine, and finance.

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