%0 Journal Article %T Competence Approach in Teaching the Topic "Tangent Plane and Normal" %A Dmitrieva, I.M. %A Ivanov, G.S. %K surface, tangent plane, normal, partial derivatives, surface curvature, Dupin indicatrix, milling. %J Geometry & Graphics %D 2018 %N 6 %P 7 %I INFRA-M Academic Publishing LLC.