(15%) 9. Let f be a function of two variables defined by x³ y , if(x, y) = (0,0) f(x, y) = { x² + y² 0 , if(x, y) = (0,0
Posted: Thu Jun 02, 2022 11:59 am
(15%) 9. Let f be a function of two variables defined by x³ y , if(x, y) = (0,0) f(x, y) = { x² + y² 0 , if(x, y) = (0,0) Prove the following statements by definition to deduce that f is a counterexample to " differentiability continuity and existence of all directionalderivatives". ● (A) f is continuous at (0,0) ● (B) Daf(0,0) exists for all unit vector u = (a, b), a² + b² = 1 • (C) f is not differentiable at (0,0)