## Where did cotQ come from?

I won't write the whole thing(unless asked for from you guys), but I just want to ask where did cotQ come from in canonical transformation.

For instance, F(q,Q) = 1/2p$_{(q,Q)}$q => $\partial$F/$\partial$q=1/2p+1/2*$\partial$p/$\partial$q=1/2(p+qcotQ)=p.
What is this? How did the last things come from??

 PhysOrg.com physics news on PhysOrg.com >> Iron-platinum alloys could be new-generation hard drives>> Lab sets a new record for creating heralded photons>> Breakthrough calls time on bootleg booze
 Recognitions: Science Advisor How should we know, if you don't give the generator of the transformation explicitly?
 Sorry my bad, I didn't know why this was important (if u may also clear that) but it is F=1/2*p*q, and this was at the end of an exercise, and what I posted in my original question, was a remark under the question! But I guess related to it

## Where did cotQ come from?

I am struggling alone in understanding classical mechanics!