Solving simultaneous PDEs using FEMLAB

Homework Statement

I want to solve the following two interlinked (simultaneous) Partial Differential Equations using FEMLAB. The equations are:
$$$\frac{\partial^2 \psi}{\partial^2 x} = - \frac{q}{\epsilon} p$ $p \frac{\partial^2 \psi}{\partial^2 x} + \frac{\partial \psi}{\partial x} . \frac{\partial p}{\partial x} = 0$ q = 1.6e-19 $\epsilon = 3*8.854e-12$$$

Homework Equations

How to Solve using FEMLAB?? or any PDE solver...

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