Enter your function in the edit field to see its graph. [br][br]You can use the provided parameters: a, b, c, h in your input, and then change their values with sliders.[br][br]You have access to vertical traces of the surface (check an appropriate check box). [br][br]You have access to the tangent lines to those vertical traces, as well as to the tangent plane at the point (x0, y0, f(x0, y0)).