URL：https://media.cheggcdn.com/study/89d/89d3424d-49ba-4879-8f6b-f490cff927ee/Screenshot2024-04-05at9.17.11AM.png
掲載元：https://www.chegg.com/homework-help/questions-and-answers/1-point-let-vec-f-ax-4z-x-cz-7y-mx-b-c-m-constants-suppose-flux-vec-f-closed-surface-zero--q164687887
