Calculus

EMPhillips1989 · 2008-03-10 23:18:02

let

i've found the gradient of f as

i now need to find the unit normal to the surface

at the point (2,-2,2)
does anyone know a formula i can use to find this? please help!

Last edited by EMPhillips1989 (2008-03-11 00:39:22)

luca-deltodesco · 2008-03-10 23:57:32

the gradient normalised IS the normal, substitute the values of x,y,z into the gradient function, and normalise the vector.

also, you should have -2xk not +2xk

Last edited by luca-deltodesco (2008-03-10 23:58:14)

EMPhillips1989 · 2008-03-11 00:36:02

So is this correct?

luca-deltodesco · 2008-03-11 02:04:29

yeh, thats fine, but then you have to normalise it for the unit normal

so:

Ricky · 2008-03-11 05:48:27

If my memory serves me right, this is the proper symbol for gradient:

Monox D. I-Fly · 2017-03-16 18:41:34

Ricky wrote:

If my memory serves me right, this is the proper symbol for gradient:

I... never knew that despite I am a math graduate and often spend my time in math forums. In my country, gradient is generally symbolized as m.

zetafunc · 2017-03-16 22:12:58

Ricky wrote:

If my memory serves me right, this is the proper symbol for gradient:

Indeed, though is my preference. typically denotes the Laplace operator.

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