I would like to further extrapolate on the invisibility vs. detect magic question discussed previously.
There is a 30 X 30' room in a certain dungeon. Inside of this room against the wall opposite the door is an enemy who has invisibility cast on himself. He has on his belt a +3 vorpal Sword. So there he is in the room with invisibility cast.
There are a party of adventurers coming down the corridor and entering the room. The adventuring wizard cast detect magic and has been concentrating as they've been walking down the corridor. Detect magic is of course a 90 degree cone going out in front of the adventuring wizard.
The party enters the 30's square room mentioned above. The wizard concentrates for three rounds while facing into the room. This would put the inivisible enemy easily within' the scope of the detect magic spell that is being concentrated on by the adventuring wizard
1. Aside from the party, how many auras would the detect magic pick up?
-My answer, the detect magic would pick up 2 auras outside the party, a minor illusion aura, and a moderate-strong aura of Alteration(the sword)
2. Could the Adventuring wizard accurately target a spell against the invisible enemy?
-my answer, yes
3. If so, would there be a miss chance?
-my answer - I would still impose a 20% miss chance, perhaps as high as 50%
4. Assuming this invisible enemy is extremely crafty, and is hidden in the shadow of a dias that happens to be near him, would the adventuring wizard detect him, if he did, what would the miss chance be (assume 50% coverage) and would the adventuring wizard have to roll a spot to beat the enemy's hide even AFTER detecting the enemy via detect magic....
-my answer 9/10ths cover, and no the adventuring wizard would not have to roll a spot to detect the enemy, but would to target him.
5. Final question for all the bonus points- If the adventuring wizard thought to cast a true seeing spell on himself that is still in effect, and the Enemy was hidden as well as invisible, would the Adventuring wizard have to roll a spot to see him even after detecting him
-my answer, yes. The adventuring wizard would have to roll a spot to detect the hiding enemy despite his invisibility