Is spin angular momentum increasing in a gyroscope?

[applestrudle]

In my textbook there is an equation for the precession frequency:

Ω = τ/Iω

The derivation in the book shows no difference in the spin angular momentum at time t = 0 and t = delta t but when I tried it I got that the denominator of the above equation must be the 'new' angular momentum (at t = delta t)

If the spin angular momentum is increasing with time wouldn't that means the precession frequency would be decreasing but my textbook says constant velocity

 

[Khashishi]

I'm not sure what you are asking, but angular momentum is conserved, so it can't increase without some external torque. The moment of inertia could change if the gyroscope changes shape, but the angular momentum should stay constant, or be slowly decreasing due to friction.