BHATTACHARJEE, P. R. Use of tangent and normal vectors for the derivation of equations of tangent and normal. International journal of physics and mathematics, [S. l.], v. 7, n. 1, p. 7-15, 2024. DOI: 10.21744/ijpm.v7n1.2287. Disponível em: https://sloap.org/journal/index.php/ijpm/article/view/2287. Acesso em: 2 may. 2026.