Advanced Mathematics - Chapter 8 differential calculus of multivariate functions 1

1 Through infinitesimal * Bounded is still equal to infinitesimal to solve

2 Prove that the limit of binary function does not exist

3 Partial derivatives of binary functions and the determination of continuous existence

4 Partial derivatives of multivariate functions exist , The relationship between differentiability and continuity ？

5 How to find the total differential of binary function from the partial derivative of binary function

6 Judge the differentiability of binary function at a certain point

7 Binary function is differentiable at some point, but partial derivative is discontinuous