multivariable calculus

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 ___...

Consider a function f(x,y,z) given by f(x, y, z) = (x² + y² - 2z²) (y² + z²) The partial derivative of this function with respect to x at the point,x = 2, y = 1 and z = 3 is

Consider a function $$f\left( {x,y,z} \right)$$ given by $$f\left( {x,y,z} \right) = \left( {{x^2} + {y^2} - 2{z^2}} \right)\left( {{y^2} + {z^2}} \right).$$ The partial derivative...