Differential Equations
Introduction

Basic Conceptions

First-Order Differential Equations

Directly Integrable Equations
  Motion of a Body - Problem 1
  Motion of a Body - Problem 2
  Motion of a Body - Problem 3
  The Spontaneous Radioactive of Substance

Separable Equations
  Motion of Particals in Viscous Fluid
  Newton's Model of Cooling
  Model of Population

Separable Equations
  Motion of Particals in Viscous Fluid
  Newton's Model of Cooling
  Model of Population

Homogeneous Equations

Linear Equations

Bernoulli Equations

Exact Differential Equations

Differential Equations of Higher Orders

Basic Conceptions
Equations of Special Kinds

Some Graphic Illustrations using MATLAB

Clich here to go to Indefinite Inegrals


Clich here to go to Definite Inegrals




Basic Conceptions
Real-Life Problems:   Motion of a Body - Problem 1 » Motion of a Body - Problem 2 » Motion of a Body - Problem 3 » The Spontaneous Radioactive of Substance » Motion of Particals in Viscous Fluid » Newton's Model of Cooling » Model of Population

In this section we introduce the basic notation and terminology of differential equations.

The general form of a differential equation of the first order is

,         (*)

where x is the independent variable; y = y (x) is unknown function;  y' is the derivative of the function.

Solution of a differential equation is a function y = y (x), which being substituted into the equation reduces it to an identity.

The general solution of equation (*) is a function , which is the solution of (*) for any values of a parameter C. If to substitute for C some value, we obtain a particular solution of equation (*).

Sometimes the solution can be found only in the implicit form. If the equation

,

determines the general solution of (*), then it is called the general integral of the differential equation.

If there is given an initial condition y (x0)=y0 in addition to equation (*), then it is necessary to find the particular solution which obeys the initial condition.


Examples
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© 2004-2010 by Norbert Grunwald and Valery Konev