bang (one's) head against a brick 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 brick 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 brick wall trying to convince everyone.

Common Names:

Name	Pronounced	Usage
Mavourneen	-	Irish
Kilian	KEE-lee-ahn (German)	German, Irish, French
Epiphany	i-PIF-ə-nee	English (Rare)
Rati	-	Hinduism, Indian, Hindi
Virginia	vər-JIN-yə (English), veer-JEE-nyah (Italian), beer-KHEE-nyah (Spanish)	English, Italian, Spanish, Portuguese, Swedish, Romanian, Ancient Roman
JoaquÍN	hwah-KEEN	Spanish