2.3.31 Gradient and directional derivative
condition: Does the function \( f(x, y)=x^{3}+2 x^{2} y+2 \) at the point \( A(2 ; 2) \) increase or decrease in the direction to the point \( B(2 ; 2) \)?
Calculation of the gradient and derivative in a given direction of functions of several variables.