# not sure if this equation is right??Watch

#1
I need to find the set of points where F is not a local diffeomorphism. I'm told it's not a LD when , therefore

But if you look at the end of the question, it states what is- which no matter how I re-arrange it, is not the same to what I have just written above. Am I getting it wrong?

This is the question if it's needed:
Consider the smooth map given by the equations:

The Jacobi matrix is:

and the determinant (Jacobian) is:

any help really appreciated!!
0
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7 years ago
#2
(Original post by hey_venus)
any help really appreciated!!
If it's just a case of evaluating the determinant then a quick check with n=2 say will tell you, if it's anything else, you need someone more up to speed with this.
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#3
(Original post by ghostwalker)
If it's just a case of evaluating the determinant then a quick check with n=2 say will tell you, if it's anything else, you need someone more up to speed with this.
thanks i've just substituted 2 for n in both versions of the but it still comes out different:

the first version i get:

but if i do it to the original i get
.

i'm really not sure how the lecturer got the first version from the original :s this is annoying!
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quote
7 years ago
#4
(Original post by hey_venus)
thanks i've just substituted 2 for n in both versions of the but it still comes out different:

the first version i get:

but if i do it to the original i get
.

i'm really not sure how the lecturer got the first version from the original :s this is annoying!
Your evaluation of the first one's not correct; should be:

Which when you compare it with the original, makes me think the final squaring shouldn't be there, in which case your first version should be and they are equal.
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