Hello! I have a question about a problem I am trying to work out.(adsbygoogle = window.adsbygoogle || []).push({});

The question asks to find the directional derivative of f(x,y,z)=x^2+yz at the point (1,-3,2) in the direction of the path r(t)=t^2i + 3tj+(1-t^2)k.

Ok, first do I find the derivative of r(t) to get 3j +t(2i-2k) and then use 2i-2k as the direction vector to find the unit vector? Then the unit vector would be

1/sqrt[2] (2i-2k) and then find the scalar product of the unit vector with the gradient of the f function?

my final answer was 5*sqrt[2]. Did I work this out right? I am studying for an exam and that is one of the problems I think will be on it.

Thanks!

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# Homework Help: Directional Derivative Problem

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