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
AfËRdita	ah-fər-DEET-ah	Albanian
Anand	-	Indian, Hindi, Marathi, Tamil, Telugu, Malayalam, Kannada, Gujarati, Bengali
Teodor	te-AW-dawr (Polish), TE-o-dor (Croatian)	Swedish, Norwegian, Danish, Romanian, Czech, Slovak, Polish, Serbian, Croatian, Slovene, Hungarian,
Boyle	[bɔil]
Ali	['a:li]
Shai	-	Hebrew