- #1
Granger
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Homework Statement
$$f:\mathbb{R^2}\to\mathbb{R}$$ a differentiable function in the origin so:
$$f(t,t) =t^3+t$$ and $$f(t,-2t)=2t$$
Calculate $$D_vf(0,0)$$
$$v=(1,3)$$
Homework Equations
3. The Attempt at a Solution [/B]
I have no idea on how to approach this problem.
I know that because f is differentiable we have
$$D_vf(0,0)= Df(0,0)v$$
So I should be able to determine the partial derivatives. But how can I do it?
My biggest obstacle is not knowing the value of $$f(0,0)$$ (and therefore not being able to take limit definition of partial derivative)