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04-15-2013
07:46 PM

04-15-2013
07:46 PM

Hello All

I'm setting up a worksheet to enable me to check my workings for when I need to solve a *two or three dimensional scalar field* by hand (*cylindrical & spherical polar coordinates).*

Mathcad partially differentiate some but not all and it flags some variable. Also, I cannot get **grad** f or |**grad **f|.

I'm obviously setting up something incorrectly.

Could someone point me in the right direction, please?

I'm enclosing my worksheet.

Solved! Go to Solution.

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04-16-2013
05:26 PM

04-16-2013
05:26 PM

Thank you Alan for the corrected worksheet

Question: I've noticed that MathC does not return a *scalar* for | **grad** f | . Should it not return a scalar value instead of a *vectorial* value, as I'm not working out | **grad** f | in the direction of its *unit vector grad f / | grad f | *?

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04-16-2013
04:37 AM

04-16-2013
04:37 AM

Re: Scalar fields: partial derivatives, grad f and |grad f|

The attached shows some modifications to the cylindrical section. It might (or might not!) be of some help.

Alan

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04-16-2013
05:26 PM

04-16-2013
05:26 PM

Thank you Alan for the corrected worksheet

Question: I've noticed that MathC does not return a *scalar* for | **grad** f | . Should it not return a scalar value instead of a *vectorial* value, as I'm not working out | **grad** f | in the direction of its *unit vector grad f / | grad f | *?

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04-17-2013
02:55 AM

04-17-2013
02:55 AM

Re: Scalar fields: partial derivatives, grad f and |grad f|

Rosanella di-Costanzo wrote:

Thank you Alan for the corrected worksheet

Question: I've noticed that MathC does not return a

scalarfor |gradf | . Should it not return a scalar value instead of avectorialvalue, as I'm not working out |gradf | in the direction of itsunit vector?gradf / |gradf |

It does return a scalar value. However, to see this more clearly it's probably best to define ep as a function and then insert specific values when it is called. For example:

(Actually, ep need only be defined as a function of x and y. I've included z above, but it's superfluous).

Alan

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04-19-2013
07:57 AM

04-19-2013
07:57 AM

Re: Scalar fields: partial derivatives, grad f and |grad f|

Many thanks Alan