[maxter]

It's more complex than that. The classical example of optimal bluffing frequency (a river bet) assumes that you have nothing or the nuts, so we bluff 1/(pot+2) of the time to avoid being exploited and make the villian indifferent.

There are some differences in the example you provided (let's ignore if this is a good board to bluff or our opponentt tendencies). When there are cards to come, you are in fact semibluffing, so you'll win sometimes when you are called against some of his bluff-catchers (as yourface said). That inclines us to semibluff slightly more than betsize/pot+2 of the time.

On the other hand, when we .raise for value, we don't have the nuts 100% of the time. We are raising with certain equity against his range. We may raise for value and still lose to a better hand or a worse hand that improves on the river, so that should incline us to bluff less

An approximation of the optimal actions here must take into account 1) What range we have and 2)What we do with each hand in our range. The key is balancing semibluff raises and value raises in a manner our opponent can't exploit us easily (optimal strategy is impossible to calculate). A good idea is thinking that our opp knows our strategy but we don't care because he won't improve his EV adding more or less hands/call-downs/re-bluffs/value re-raises.

I recommend you The Mathematics of Poker for deep explanations on this topics.