(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

In the first paragraph, I know its missing a function which they did not put, g. Without puting ∂g/∂x but simply putting ∂/∂x, is that equation even mathematically correct? I know they are "filling in the g later" but does this corrupt the in-between steps in anyway?

In the second paragraph, from step 1 to step 2:

-how can they simply " take out the f "?

-how can they simply replace 'f' by 'g'? would this imply that f = g? (which is obviously not the case)

3. The attempt at a solution

I have come to several conclusions to make sense of what's happening:

1. The term ' ∂/∂x ' by itself is meaningless, only when you slap it together with a function like in (∂/∂x)(∂g/∂x) would it mean that you are partially differentiating 'g' twice with respect to 'x'.

I only started the topic of partial differentiation today, and the methods presented here seems weird to me...

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# Homework Help: Partial derivative: taking out the 'f'

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