PHAN, Trong Thu. Using the tangent line in proving the inequalities. Dong Thap University Journal of Science, [S. l.], n. 12, p. 115–120, 2015. DOI: 10.52714/dthu.12.4.2015.194. Disponível em: https://dthujs.vn/index.php/dthujs/article/view/830. Acesso em: 8 sep. 2024.