# Partial Differential Equation? What is this?

The professor passed this out today for homework and I have no idea how to even get started. If someone could tell me what type of problem this is I could look it up in the textbook but I can't find anything similar. I couldn't figure out how to insert all of the symbols so I attached the problem as a .gif

#### Attachments

• 22.4 KB Views: 345

Related Calculus and Beyond Homework Help News on Phys.org
HallsofIvy
Homework Helper
What exactly is your problem? The paper leads you step by step through the solution. It says

"Seeking a solution of the form u= f(x) cos($\omega$t)+ g(x) sin($\omega$t), show that ...."

Okay, put that into the differential equation and see what must be true of f and g in order to satisfy the equation.

Last edited by a moderator:
I have been trying to figure out this problem for a week now and I am still drawing a blank on how to "put that into the differential equation." How exactly can I get started on this?

HallsofIvy
Homework Helper
Do you know how to "substitute" into an equation? The problem is askng you to substitute u= f(x) cos(t)+ g(x) sin(t) into the equation and tell what must be true of f and g in order to satisfy the equation.

I'm not sure I understand exactly what you are talking about. What am I substituting u= f(x) cos(t)+ g(x) sin(t) into? The du/dt=D*(d2u/dx2) equation?

HallsofIvy