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
Nedyalka	-	Bulgarian
Menashe	-	Hebrew
Berko	-	Western African, Akan
Merletta	mur-LET-ə	English (Rare)
Mukul	-	Indian, Hindi
Sanctius	-	Late Roman