beat (one's) head against a stone 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 beating my head against a stone wall trying to understand this math equation. Some people are never going to agree with you on this, so it's no use beating your head against a stone wall to try and convince everyone.

Common Names:

Name	Pronounced	Usage
Aldith	-	Medieval English
JolÁNka	-	Hungarian (Rare)
Patrice (2)	-	English
Leah	[liə]
Mairwen	-	Welsh
HÁLfdan	-	Ancient Scandinavian