So I looked over the wiki, and skimmed through the forums and either its not there, or I'm just blind and missing it, but I am looking for a formula to give me the attackers min attack needed to hit for damage cap each hit based on a targets defense. so basically if player A has a damage cap of 500 and a defense of 10k, how much attack would Player B have to have to guarantee that they hit player A for their damage cap damage every hit?

288000 to hit damage cap every time. without trinity cores auto evasion node

346000 with trinity cores and auto evasion node.

Ok, but whats the formula based on damage cap & defense to arrive at those numbers?

for examples:

player A, dmg cap of 1k, 20k defense, equation to figure out player b's min attack to hit for full cap

player A, dmg cap of 2k, 35k defense, etc, etc...

Damage per shot = tanh( attack*(random(0.6 to 1.666)) / (defense * 5) ) * damagecap

Ok, i saw that equation, but that's not quite what I am looking for (at least I dont think)... my understanding is thats how you would calculate how much damage per shot you would do against someone, yes?

I want a equation to figure out what the min attack would be needed to ensure always hitting for cap, for example lets say my damage cap is 1500, and I have a defense of 18k, i'm looking for an equation to figure out what the min attack rating that someone who attacked me would need to hit me for max damage every hit.

Not an equation but a rule of thumb: If your attack is 22x their defense you will be hitting for damage cap almost all of the time.

It is this formula you just have to solve it and make a few assumptions.
First that Damage per shot = damage cap
Second that is it the lowest possible outome so

damage cap= tanh( attack*0.6 / (defense * 5) ) * damagecap
divide both sides by damagecap gives

1= tanh( attack*0.6 / (defense * 5) )

tanh^-1(1) = undefined. So what you need is a number it can reach that the game would round up to the next integer up, damage cap-0.5. Then just rearrange in terms of attack.

attack = (defense*5*tanh^-1((damage cap-0.5)/damage cap))/0.6