Please send the solution to the problem given in the attachment.

yes if you don't know the function then you are correct....and if you know function is continuous then you can compute it different manner like if you take partial derivative first...

visit through this link https://www.khanacademy.org/math/multivariable-calculus/multivariable-derivatives/partial-derivatives/v/symmetry-of-second-partial-derivatives

If f is a continuous and differential function and second order partial derivatives of f is continuous then Fxy = Fyx. and u are right . must visit through this link. ht...