Alright, I'm sure this has come up before, but from doing searches I haven't found any posted answers or any recently updated threads where this has been asked but:

What's the formula for how Armor Rating works in Skyrim?

Does it use a diminishing returns formula such as TD=D*(1-AR/(AR+100)) where TD=Total Damage, D=original Damage from attack and AR=Armor Rating?

Is it a flat percentage such as TD=D*(1-AR/4000)?

Is it a damage reduction formula, such as TD=D-AR/10?

Some threads have mentioned smithing/enchanting over 2000 AR....

It would really be nice to know how much protection 10-50 points of AR gives me so when I equip my character I can decide if it's worth taking a slight AR hit for some cool enchanted effect or just because I like the way the armor looks. The problem with hidden formulas such as this is that I can not make an informed decision on my equipment.

This is also frustrating in other areas such as what leveling up a skill actually does. For example: does level 50 destruction do more damage or have cheaper spells than 25 destruction? Does 50 lockpick give me a larger sweet spot or make picks more durable than 25 lockpick? Come on Bethesda, I want my FOIA! Open books! No more back-room skooma deals! It's fine for someone who wants to tweak out his character to discover the answers by trying on new outfits in front of a mudcrab like it was some department store, but for people who just want to play the game, having an obscure armor rating system makes things really frustrating.

(If it is some kind of flat percentage system, and the armor goes up to 2000, that makes the differences between nearly any armor at all for the first 20 hours of the game pretty much negligible, especially considering weapons are only doing 10-40 damage)

p.s. some people are complaining about magic damage that doesn't scale, but theoretically if armor rating doesn't affect magic damage, and armor scales at roughly the speed damage does, doesn't that mean that damage doesn't scale either, putting it on par with magic damage? At early levels when I saw how slowly health scaled I was really overjoyed. I thought that meant endgame fights wouldn't be interminable chipping-away-the-huge-health-block scenarios.

I read a post somewhere on the forums where a guy experimented by taking on a saber cat with an AR of around 100 and an AR of around 150. The extra 50 points increased his success rate of beating the cat from nearly 0 to 50-50.

As far as armor skills go, I had a necklace that increased my light armor skill by 12. IIRC that led to an increase AR of a little less than 10%, though that was early in the game (I think my AR was in the low 60s at the time and I got 5 additional points with the necklace).

As a play issue, I prefer having the formulas hidden as I then tend to view things less mathmatically and more from a "what do I want to do" perspective. It would be helpful if there were at least rough guidelines though. That's why I found that other post somewhat helpful.

I understand what you are saying about hidden formulas preventing some people from overthinking things. I find myself stressing a lot more about it though because I don't know.

It's just really frustrating to look at my inventory and say "I know exactly what +30 mana will give me, I have no clue what +12 armor rating will give me."