TANGENT

(Lat. tangens; from tango, I touch.) In Geometry, the tangent to a curve is a straight line which meets or touches the curve without intersecting it. The nature of the tangent may be explained as follows: Let A P B be an arc of a curve, and let the straight line TAB m intersect it in two points, A P><! v • andB. Conceive the straight line to revolve about the point T. When it comes into the position Tab the intercepted arc a P b is shortn er than A P B, or the points [s. 1229]