Hi, and welcome to Wikipedia (if you're new here). I noticed that you've italicized some differentials — for example, converting dx to dx at Fundamental lemma of calculus of variations and Euler-Lagrange equations. Although the latter arguably makes more sense, the former is extremely common in the math literature. Wikipedia's official policy says that each article must use one or the other consistently, and that editors should not go through articles systematically changing from one convention to the other. So please do not continue. Thank you for your interest, and I hope that you enjoy editing Wikipedia otherwise. Mgnbar (talk) 21:10, 27 March 2014 (UTC)
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