rate of change

Let $(x, y) \in \Re^2$. The rate of change of the real valued function, $V(x, y)=x^2+x+y^2+1$ at the origin in the direction of the point $(1,2)$ is _________ (round off to the nea...

A quadratic function of two variables is given as f(x1,x2) = x₁² + 2x₂² + 3x₁ + 3x₂ + x₁x₂ + 1 The magnitude of the maximum rate of change of the function at the point (1,1) is ___...