I have the following function $$e(p_x,p_y,\bar{U}) = p_x a(p_x,p_y,\bar{U}) + p_y b(p_x,p_y,\bar{U})$$
Can I take the total derivative of this? I am confused about the criteria for something to be totally differentiable.
My Question:
- Is the function above totally differentiable (assuming the functions chosen aren't weird or kinky or something)?
- How can I tell if something is totally differentiable?