“…On the one hand the instructor showed that he can conceive the tangent line as the totality of a process of approaching a point on the curve through secant lines: "when I have finished approaching totally, they will be the same" (referring to the secant and tangent lines, Villabona et al, 2022). But on the other hand, he has difficulty applying Actions on that totality: in another situation involving a circle, two AIEM (2022), 21, 9-21 parallel tangent lines and another line crossing them, he could not conceive of some of the angles that were formed by the figures becoming zero in a limiting case, in which a secant line gets closer to a tangent line by means of approaching some point on the circle to another point on the circle where a tangent line was drawn.…”