Any bow. When they get close to you, they'll start to swing. Time that and start running away. Stop a little ways away and fire a couple arrows. Repeat until dead. If it's night and a lot of other stuff starts coming after you, just run away. I just started playing recently. It took me a little bit before I could take trolls + other mobs doing that same strat.

Also, if you can sneak attack with a bow before they see you, it does huge damage. If you can sneak attack with a knife you can pretty much kill them, or I believe you can kill them in one shot once leveled up.