What is supposed to be the role of the Mage class?

The Mage class is primarily a ranged damage-oriented support class that has three separate schools of magic available to them: Arcane, Fire, and Frost. The three different forms of magic schools available to the Mage make it a very flexible class to deal damage to almost any type of creature in the game. The Mage also has the strongest multiple target area of effect (AoE) damaging spells/abilities in the game. Other support functions that a Mage can provide include single target control [Polymorph], and short-term crowd control [Frost Nova/root effects]. The Mage class is also the only class that has the ability to conjure food and drink This saves a great deal of cash for the Mage and his/her friends. The Mage is very highly sought after class for groups, raids, and instance dungeon crawls.

Although the Mage is a very strong group-role class, it makes a very effective character in soloing many same-level quests and creatures on its own. The general rule is:
-Anything below your level is safe
-Anything one/two levels above your level will cost a good portion of your mana but is usually safe and you should expect resistances at around 10-25%
-Anything three levels above your level will cost you a majority of your mana and a decent supply of your health and you should expect about 50%+ resistances.
-Anything four levels above your level or higher will cost you all of your mana, all of your life, potions/mana gems, and you should expect around 75% or higher resistances. Success is not ensured and may result in an unplanned visit to the Spirit Healer in some cases.