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

find the direction of P sub 0 in the direction of A

see second post for attachment, I forgot to place it on this one.

3. The attempt at a solution

I'm only worried about the part that says g_{y}(x,y,z) = -3ze^{x}sin yz. I also don't understand the conversion of g^{x}and g^{z}.

1. why does cos change to sin? obviously its the derivative but why isn't the derivative being used in g_{x}and why is it also used in g_{z}

2. if they're taking the derivative then it doesn't look like the product rule is being used. why not?

3. I would think they would be using u substitution with the x in e^{x}but I'm better at using u substitution with integrals than with derivatives. I'm pretty sure this is the explanation for why there is a -3z and a -3y in g_{y}and g_{z}. I understand where the negative sign comes from, it's because the derivative of cos in -sin. But I don't understand where the z and y comes from.

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# Homework Help: Directional derivatives

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