Solving ode with complex numbers

Click For Summary
SUMMARY

The discussion focuses on solving the ordinary differential equation (ODE) y'' + y' + y = (sin(x))^2 using complex numbers. The user attempts to use the form y = Ae^{ix} but encounters issues when squaring the term, resulting in A^2 e^{2ix}. The hint provided indicates that (D^3 + 4D)(sin(x))^2 = 0, suggesting that (sin(x))^2 is a solution to the third-order differential equation y''' + 4y. The user is encouraged to select the appropriate particular solution from the identified solutions.

PREREQUISITES
  • Understanding of ordinary differential equations (ODEs)
  • Familiarity with complex numbers and their applications in differential equations
  • Knowledge of the method of undetermined coefficients
  • Experience with differential operators, specifically the D operator
NEXT STEPS
  • Study the method of undetermined coefficients for finding particular solutions
  • Learn about the application of complex exponentials in solving ODEs
  • Research the properties of differential operators, particularly the D operator
  • Explore the reduction of order technique for solving higher-order ODEs
USEFUL FOR

Mathematicians, engineering students, and anyone involved in solving ordinary differential equations, particularly those interested in complex analysis and differential operators.

cragar
Messages
2,546
Reaction score
3
I want to solve [itex]y''+y'+y=(sin(x))^2[/itex] and try to use
[itex]y=Ae^{ix}[/itex] but then when I square it I get [itex]A^2 e^{2ix}[/itex]
I found y' and y'' and solved for A and it didn't work I guess I could use the formula for reducing powers but I would like to try and get around that.
 
Physics news on Phys.org
hint
$$(D^3+4D)(\sin(x))^2=0$$
or
(sin(x))^2 is a solution of y'''+4y

chose the particular solution from those solutions
 

Similar threads

  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 1 ·
Replies
1
Views
3K
  • · Replies 2 ·
Replies
2
Views
3K
  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 7 ·
Replies
7
Views
3K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 4 ·
Replies
4
Views
3K
  • · Replies 2 ·
Replies
2
Views
3K