Can't remember how to do this simple definite integral

[astonmartin]

If my Force = (-gamma)(dx/dt)
velocity v = dx/dt
Mass m

(m)(dv/dt) = F = (-gamma)(dx/dt)

Now I want to integrate it over kT<= t <= (k+1)T

Rearranging gives me (dv/v) = (-gamma/m)dt

The right side integrates to (-gamma/m)(T), but how do I integrate the left side over kT<= t <= (k+1)T??

Thanks

 

[HallsofIvy]

$$\int \frac{1}{v} dv= ln(v)+ C$$

 

[astonmartin]

^but what does that give me for the definite integral?

ln [v(k+1)T / v(kT)] ?