Euler's laws of motion for a distributed mass are:

$$F = \frac{d}{dt} MV\_{cm},\ N = \frac{d}{dt} L$$

$F$ are the sum of the external forces, $M$ the total mass, $V\_{cm}$ the velocity of the centre of mass. $N$ are the sum of the moments of the external forces about some given point, L the total angular momentum about the same point.

If a gyroscope is supported at its base with its axis horizontal, it precesses at a constant angular velocity. Using the above equations, how does one show this?