Question

in the applet given for directional derivative the directon of gradient is being showed smewhere along x-y plane but the direction of gradient is supposed to be perpendicular to the curve??
please check it!!!

Answer 1

ok i think your asking about a level curve if so, then you know z=f(x,y)= a bowl, ball, something in a 3d state. well if you go to a point on that 3d object well say P(x0,y0) and cut the 3d object parallel to the XY plane, then you shove that outside "cut" onto the XYplane. This may be confusing