# [SOLVED]vibrating beam concept question

#### dwsmith

##### Well-known member
If we had a beam fixed at $x = 0$ and on pin rollers at $x = L$, why would $u_{xx}(L,t) = 0$ and $u_x(0,t) = 0$.

$u(0,t) =0$ since the at $x = 0$ the beam is fixed and $u(L,t) = 0$ since the beam is on roller and wouldn't have any displacement, correct?