GETTHETANGENT draws the tangent to a curve at a point that the user chooses by a mouse-click and displays a text-box giving the slope and the y-intercept value of this tangent in the current axes.

GETTHETANGENT(H) gives the focus to the axes whose the handle is H and processes in theses axes.

[SLOPE, INTERCEPT]=GETTHETANGENT returns the slope and the Y-intercept of the tangent to a curve belonging to the current axes and at a point friendly choosen by the user.