Second derivative

Hi. I'm stuck and need your help/suggestion. I need to find the second derivative of g : \mathbb{R}^m \to \mathbb{R} defined by



I already found a first derivative ([math]\forall v \in \mathbb{R}^m [\math]) :



But I'm stuck there. Should I search (\delta_v f)' ? I have no idea how to proceed.

Suggestion?

Oh, and I hope LaTeX works.

Did you try wolfram alpha?

>>2

Thanks but it's a a bit too advanced for Wolfram Alpha. Nobody? I think it's first or second year level.

Try factorials, they get things going.

I have no idea why I said that.