When writing math papers, one sometimes has to refer to some famous theorems, for instance, the Pythagorean theorem.
Shall I write "by Pythagorean theorem", or "by the Pythagorean theorem". When shall I use the article "the"?
English Language & Usage Stack Exchange is a question and answer site for linguists, etymologists, and serious English language enthusiasts. It only takes a minute to sign up.Sign up to join this community
This Google ngram shows what others have done in published books.
Notice that 'by Pythagorean theorem' has only one occurrence.
"by Pythagorean Theorem"
For example, "I solved this equation using Pythagorean's Theorem," or, I solved expression 6 by using Pythagorean's Theorem."
I hope this helps!😁