https://gateoverflow.in/968/gate2003-85
How in the above question the functional dependency (date of birth -> age) is a partial functional dependency. (As told in the selected answer for this question)
Because according to navathe the definition of partial functional dependency is
A functional dependency X -> Y is a partial dependency if some attribute A belongs to X can be removed from X and the dependency still holds; that is, for some A belongs to X (X - {A}) -> Y.