Consider the production function:

y(x1, x2) = x2/1 + x2/2

* i put the "/" signs just to show the first number above the 2nd, its not actually divided*

can someone try to explain how I go about finding the second-order total differential to find if it is concave or convex?

I'd appreciate it if you can explain as simply as possible(in words not math)

thanks a lot in advance!