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Normal to a curve

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Old   October 3, 2003, 03:40
Default Normal to a curve
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Pr
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Is there any mathematical formula available for getting a normal or perpendicular to a curve from some arbitrary points. Thanks for any help Pr
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Old   October 3, 2003, 11:53
Default Re: Normal to a curve
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xueying
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Map the curve to an easy shape, and the mapping if matrix F.

! ==> Normal

! recall: n = cofF . N / mu in rheology class note

! Fij = dx_i/dxi_j = XY_XIETA

!

! -T

! F . N

! n = ------------

! -T

! | F . N |

!

n is the unit normal vector that you want, N is the unit normal vector in reference domain.
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Old   October 4, 2003, 13:01
Default Re: Normal to a curve
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TPallidum
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Given some points on a curve, use your favorite method to numerically evaluate the gradient.
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Old   October 6, 2003, 05:52
Default Re: Normal to a curve
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Ag Gaire.
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n = -(GRAD Phi)/|GRAD Phi|). See Anton, "Calculus" for an excellent explaination of all sorts of this type of idea.
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Old   October 6, 2003, 06:08
Default Re: Normal to a curve
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Pr
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Hey thanks for the solution. But actually I want to argue with your answer. You had written for gradients.I can calculate gradient of curve at certain discrete points at which function or curve is defined.let us say I have 50 points I can get 50 values. But from arbitrary point(A) which does not lie on the curve I want to find the normal.so one or more lines from point A to the 50 points on the curve will be normal. This procedure becomes time consuming when curve ponts increases. So I want to ask here is there any other method to do this. Pr
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