1. The problem statement, all variables and given/known data If f(x) is a scalar-valued function, show that ∂ƒ²/∂xi∂xj are the components of a Cartesian tensor of rank 2. 2. Relevant equations N/A 3. The attempt at a solution I don't even know where to begin. We began learning tensors in multivariable calculus (though I don't think this is supposed to be a part of our curriculum) and this question came up. I'm not sure at all how to answer it. Any help in understanding this problem would be hugely appreciated, even if it doesn't solve the entire thing. Thank you.