tangent

TANGENT noun

[ C ] uk/ˈtændʒənt/ us
a straight line that touches but does not cross a curve

касательная in a triangle that has one angle of 90°, the ratio of the length of the side opposite an angle less than 90° divided by the length of the shorter of the two sides that are next to the angle

тангенс (математический)
Сравнитеcosinesine Идиомыgo off at/on a tangent