- #1

Usuiisu

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## Homework Statement

Rewrite this in terms of f, f, ∂f/∂x, and x:

∂f(x,y)/∂(%Δx) = ∂f(x,y)/∂(d log(x) )

## Homework Equations

∂(%Δf(x,y))/∂(%Δx) = ∂logf(x,y)/∂log(x)= ∂f(x,y)/∂x*x/f(x,y).

∂f(x,y)/∂log(x)=x∂f(x,y)/∂x

## The Attempt at a Solution

I found that (%Δx) can be written as the differential of log(x):

∂f(x,y)/∂(%Δx) = ∂f(x,y)/∂(d log(x) ).

But the partial of derivative of differential of the variable throws me off. It seems like the valid problems that people may have in real world: how much the level of function changes if you increase 1% of the variable, but I can't find anything on it.