We always use a positive tag question after a negative sentence:
You shouldn't take this medicine, should you?
We use a negative tag question after a positive sentence:
She must leave early, mustn't she?
But when there is a negating prefix on the adjective (impatient vs. patient) after the verb "to be", then the sentence is negative in meaning. Does this mean the tag should be positive?
Which is correct, A or B?
A: I am impatient, am I?
B: I am impatient, aren't I?
A: The class was dismissed, was it?
B: The class was dismissed, wasn't it?