Bernoulli - Maple Help
For the best experience, we recommend viewing online help using Google Chrome or Mozilla Firefox.

Online Help

All Products    Maple    MapleSim


Solving Bernoulli's ODEs

 

Description

Examples

Description

• 

The general form of Bernoulli's equation is given by:

> 

Bernoulli_ode := diff(y(x),x)+f(x)*y(x)+g(x)*y(x)^a;

Bernoulli_ode≔ⅆⅆxy⁡x+f⁡x⁢y⁡x+g⁡x⁢y⁡xa

(1)
  

where f(x) and g(x) are arbitrary functions, and a is a symbolic power. See Differentialgleichungen, by E. Kamke, p. 19. Basically, the method consists of making a change of variables, leading to a linear equation which can be solved in general manner. The transformation is given by the following:

Examples

> 

with⁡DEtools,odeadvisor

odeadvisor

(2)
> 

odeadvisor⁡Bernoulli_ode

_Bernoulli

(3)
> 

with⁡PDEtools,dchange

dchange

(4)
> 

ITR≔x=t,y⁡x=u⁡t11−a

ITR≔x=t,y⁡x=u⁡t11−a

(5)

and the ODE becomes

> 

new_ode≔dchange⁡ITR,Bernoulli_ode,u⁡t,t:

> 

new_ode2≔solve⁡new_ode,diff⁡u⁡t,t:

> 

op⁡factor⁡combine⁡expand⁡new_ode2,power

ⅆⅆtu⁡t=a−1⁢g⁡t⁢u⁡t−1a−1a⁢u⁡taa−1+u⁡t⁢f⁡t

(6)

This ODE can then be solved by dsolve. Afterwards, another change of variables will reintroduce the original variables x and y(x).

The present implementation of dsolve can arrive directly at a general solution for Bernoulli's equation:

> 

ans≔dsolve⁡Bernoulli_ode

ans≔y⁡x=ⅇ∫f⁡xⅆxa−1a⁢∫ⅇ∫f⁡xⅆx⁢g⁡xⅇ∫f⁡xⅆx⁢aⅆx+c__1−∫ⅇ∫f⁡xⅆx⁢g⁡xⅇ∫f⁡xⅆx⁢aⅆx1a−1⁢ⅇ∫f⁡xⅆx⁢aa−1

(7)

See Also

DEtools

odeadvisor

dsolve

quadrature

linear

separable

Bernoulli

exact

homogeneous

homogeneousB

homogeneousC

homogeneousD

homogeneousG

Chini

Riccati

Abel

Abel2A

Abel2C

rational

Clairaut

dAlembert

sym_implicit

patterns

odeadvisor,types