Answer Happy

True or False, please explain.
h) Let f(x,y) be any function of two variables whose partial derivatives exist. We can always find the derivative in the direction of any vector. (i) Let f(x,y) be any function of two variables whose partial derivatives exist. The direction in which the function f(x,y) is not changing at the point (x0​,y0​) is the opposite direction of ∇f(x0​,y0​). (j) We can always find an arc length parameterization for any vector valued function.