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

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




The Bernoulli Equations
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

The Bernoulli Equation is a differential equation of the form

,

where n is any rational number except for 0 and 1.

The technique of solving Bernoulli equations is just the same as that of linear equations.

Let us introduce a new dependent variable  u(x) by means of the equality

y = u(x)v(x).

This variable satisfies the equation

,

where the function  v(x) is a particular solution of the equation

and hence,

.

Then the equation for u(x) is transformed to the following form

,

which can be rewritten as a separable equation,

.

By integrating, we obtain

.

Thus,

,

and the general solution of the given equation is

y = u(x)v(x).


Examples
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