# Math Help - beam equation

1. ## beam equation

Solve equation:

$-u_{xxxx}(x,t)=\lambda u(x,t)$, $0
$u(0)=u(L)=0$, $u_{xx}(0)=u_{xx}(L)=0$

2. ## Re: beam equation

Hi ,

Using Matlab Dsolve function i get that u=0; no beam deflection!

3. ## Re: beam equation

You don't really need "DSolve". The general solution to any linear homogeneous differential equation is a linear combination of the elementary solutions. The conditions that all values be 0 then must give u identically equal to 0 as the solution. (And it should be easy to see that u= 0 for all x does satisfy the equation and additional conditions.)