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mathstina
Group Title
Find the directional derivatives of the following functions at the given points P in the direction of the vectors v.
f(x,y,z) =√xyz , P (3,2,6) , v =<1,2,2>
 2 years ago
 2 years ago
mathstina Group Title
Find the directional derivatives of the following functions at the given points P in the direction of the vectors v. f(x,y,z) =√xyz , P (3,2,6) , v =<1,2,2>
 2 years ago
 2 years ago

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piscez.in Group TitleBest ResponseYou've already chosen the best response.0
find the derivatives of the function x, y and z seperately, by keeping the other 2 variables constant in each case. Think of a smart way to keep the other 2 variables constant!
 2 years ago

mathstina Group TitleBest ResponseYou've already chosen the best response.1
ok, i tried to work out. is the ans 1?
 2 years ago

TuringTest Group TitleBest ResponseYou've already chosen the best response.1
what is you function?\[f(x,y,z)=\sqrt{xyz}\]or\[f(x,y,z)=\sqrt xyz\]?
 2 years ago

mathstina Group TitleBest ResponseYou've already chosen the best response.1
the first one
 2 years ago

TuringTest Group TitleBest ResponseYou've already chosen the best response.1
\[D_{\vec v}=\nabla f(3,2,6)\cdot\frac{\vec v}{\\vec v\}\]I don't think the answer is one but I haven't done it yet...
 2 years ago

Algebraic! Group TitleBest ResponseYou've already chosen the best response.0
is there an advanced equation editor available to super users that has cool features like gradient?
 2 years ago

mathstina Group TitleBest ResponseYou've already chosen the best response.1
negative one
 2 years ago

piscez.in Group TitleBest ResponseYou've already chosen the best response.0
@mathstina @TuringTest is right
 2 years ago

piscez.in Group TitleBest ResponseYou've already chosen the best response.0
@mathstina first fing the derivative of the function with respect to x, by substituting the y and x values
 2 years ago

TuringTest Group TitleBest ResponseYou've already chosen the best response.1
oh yeah, I do get 1 :)
 2 years ago

mathstina Group TitleBest ResponseYou've already chosen the best response.1
ok thanks a lot!
 2 years ago

piscez.in Group TitleBest ResponseYou've already chosen the best response.0
@TuringTest @mathstina no its not 1, atleast as per my calculations
 2 years ago

TuringTest Group TitleBest ResponseYou've already chosen the best response.1
I will show my work and you can spot a mistake if you see one...
 2 years ago

TuringTest Group TitleBest ResponseYou've already chosen the best response.1
\[\nabla f=\frac12\langle\sqrt{\frac{yz}x},\sqrt{\frac{xz}y},\sqrt{\frac{xy}z}\rangle\implies\nabla f(3,2,6)=\frac12\langle2,3,1\rangle\]\[\frac{\vec v}{\\vec v\}=\frac13\langle1,2,2\rangle\]\[\nabla f(3,2,6)\cdot\frac{\vec v}{\\vec v\}=\frac16(26+2)=1\]
 2 years ago

piscez.in Group TitleBest ResponseYou've already chosen the best response.0
@TuringTest @mathstina im sorry, your right, i made a mistake by putting all ves as +ves and vice versa. Bravo you two
 2 years ago

mathstina Group TitleBest ResponseYou've already chosen the best response.1
Its ok. u too got the same ans
 2 years ago

piscez.in Group TitleBest ResponseYou've already chosen the best response.0
i got it as 1 previously, now i have 1 :)
 2 years ago
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