(Solved): Determine the direction in which \( f(x, y)=x^{2}-5 x y+y^{2} \) has maximum rate of increase from ...

Determine the direction in which \( f(x, y)=x^{2}-5 x y+y^{2} \) has maximum rate of increase from \( P=(-4,3) \), and give the rate of change in that drection (Use symbolic notation and fractions where needed.) Rate of change \( = \) Galculate the directional derivative of \( f(x, y)=\cot ^{-1}(x y) \) in the direction of \( \mathbf{v}=-4 \mathbf{i}+\mathbf{j} \) at the point \( P=(0.5,0.5) \). Remember to nominiza the divecticn vicetor. \[ D_{4} f(0.5,0.5)= \]