## how to implement cartesian coordinates

### kash (view profile)

on 29 Mar 2013

I have a image

http://imgur.com/EOyLRe6

which consists of cartesian coordinates,plz tell how to implement these coordinates,which function must be used

Kindly help

Walter Roberson

### Walter Roberson (view profile)

on 29 Mar 2013

What is the context for that? It does not appear to be general Cartesian coordinates: it appears to be the expression in Cartesian coordinates of something like a wave function or a rotation.

kash

### kash (view profile)

on 29 Mar 2013

it is equation taken from

http://en.wikipedia.org/wiki/Navier%E2%80%93Stokes_equations

which is Navier–Stokes equations

kash

### kash (view profile)

on 29 Mar 2013

its for fluid flow

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### Walter Roberson (view profile)

on 29 Mar 2013

Use the symbolic toolbox function diff()

Walter Roberson

### Walter Roberson (view profile)

on 29 Mar 2013

8 is correct. f = x^3, and 2^3 is 8.

kash

### kash (view profile)

on 3 Apr 2013

after differentation we get 3x^2,so the answer should be 12 rite

Walter Roberson

### Walter Roberson (view profile)

on 3 Apr 2013

No, the answer for a=subs(f,[x],2) should be 8. Calculating diff(f) makes no difference to the value you find by substituting something into f.