Could someone explain who came up with the specific equation first?
makes it sound like Lagrange got it first, in 1755, then sent it to Euler.
sort of makes it sound like Euler got it first in the 1730s.
It seems like a straightforward question, but I can't find an answer anywhere. Who came up with the equation, Euler or Lagrange? And what precisely did the other man contribute to get his name on there?