In Mr. Eichholz’s AP Calculus class, students are finding tangent lines to curves in 2-D space that are not easily defined as y equals a function of x. Tangent lines touch a curve at exactly one point and resemble the curve when you zoom in close. Some of the unique curves they’re exploring include the circle, the “Folium of Descartes,” and the “Squircle” (Square-Circle).
