2.3.32 Gradient and directional derivative
condition: Does the function \( f(x, y)=x^{3}+4 x^{2} y+2 \) increase or decrease at the point \( A(2 ; 4) \), in the direction of the point \( B(4 ; 2) \)?
Calculation of the gradient and derivative in a given direction of functions of several variables.