- #1
Galadirith
- 109
- 0
Hi everyone. I am really confused at the moment learning about Second Order homogeneous linear differential equations. I lay out the background of what I would like to understand. So I understand the actual maths that goes into the diff's, but I do not understand why it should be so, given the general form of a second order homog linear diff
[tex]
a\frac{d^{2}y}{dx^{2}} + b\frac{dy}{dx} + cy = 0
[/tex]
where a, b and c are constants (i deal with just constants for now, in fairness some of this stuff in discussion will translate over when they are considered as functions of x) and y is a function of x.
I am told that the general solution of this equation is of the form
[tex]
y = Au + Bv
[/tex]
where u and v are different solutions of the differential equation and A and B are non-zero constants. But surly by that that therefor implies that for every second order diff of this form there are at least 3 distinct solutions, y = u, y = v and y = Au + Bv.
Looking around the net and in books I don't see why this has to be so. I am either given examples and then from that it is implied this must be so, or even worse it is simply stated, I find this extremely frustrating as there is no rigor in any of the stuff I have read. Could anyone provide me with information on either why this is so, or links to more in depth information. Thanks everyone :-)
[tex]
a\frac{d^{2}y}{dx^{2}} + b\frac{dy}{dx} + cy = 0
[/tex]
where a, b and c are constants (i deal with just constants for now, in fairness some of this stuff in discussion will translate over when they are considered as functions of x) and y is a function of x.
I am told that the general solution of this equation is of the form
[tex]
y = Au + Bv
[/tex]
where u and v are different solutions of the differential equation and A and B are non-zero constants. But surly by that that therefor implies that for every second order diff of this form there are at least 3 distinct solutions, y = u, y = v and y = Au + Bv.
Looking around the net and in books I don't see why this has to be so. I am either given examples and then from that it is implied this must be so, or even worse it is simply stated, I find this extremely frustrating as there is no rigor in any of the stuff I have read. Could anyone provide me with information on either why this is so, or links to more in depth information. Thanks everyone :-)