“If you can’t explain it simply, you don’t understand it well enough,” followed by “For example, we write Lagrange’s equations in functional notation as follows

“If you can’t explain it simply, you don’t understand it well enough,” followed by “For example, we write Lagrange’s equations in functional notation as follows: D(∂2L ∘ Γ[q]) − ∂1L ∘ Γ[q] = 0” Whoa Nellie! Gonna get bumpy.