bang (one's) head against a wall

To attempt continuously and fruitlessly to accomplish some task or achieve some goal that is or seems ultimately hopeless. I feel like I've been banging my head against a wall trying to understand this math equation. Some people are never going to agree with you on this, so it's no use banging your head against a wall trying to convince everyone.

Common Names:

Name	Pronounced	Usage
Petro	PE-tro (Esperanto)	Ukrainian, Esperanto
Eda (1)	-	Turkish
Lina (3)	-	Indian, Hindi
Pelagios	-	Ancient Greek
Bernie	['bə:ni]
Morta	-	Lithuanian