The function [math]f(x,y)=4-0.5\sqrt{3x^2-2.5xy^2+y^4}[/math] and several contours are graphed.[br][br]The gradient vector [b][math]\nabla f\left(x_0,y_0\right)[/math][/b] at the point [math]P_2=(x_0,y_0)[/math] is provided. The point [math]P_2[/math] can be dragged.[br][br]The point [math]P_1=\left(x_0,y_0,f\left(x_0,y_0\right)\right)[/math] identifies the function value on the surface.