Ekeland's variational principle

Ekeland's variational principle is a way to try and find the best answer to a problem. It says that if you have a problem with a certain challenge, and you can't find the perfect answer straight away, then you should at least try to find the best possible answer. To do this, you have to think about all the possible answers and pick the one that is closest to the perfect answer. This way you'll have the best possible answer even if it's not the perfect answer.