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Mistakes in Course Notes & HW Assignments

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Dan Negrut

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Unread post Tue Mar 16, 2010 10:58 am

Re: Mistakes in Course Notes & HW Assignments

There was a mistake (fixed in the uploaded slides) on slide 15, where some zero matrices in J^p were shown as being 3X3, instead of 4X4.
Pointed out by Praveen and Makarand.
Thank you both.
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ME751Anne

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Unread post Sat Mar 20, 2010 3:31 pm

Re: Mistakes in Course Notes & HW Assignments

In HW9, I think you mean gamma_hat rather than just gamma. On slide 24, the gamma hat for DP1, I don't think a_j_T and a_i_T in the expressions should be dotted.
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ME751Anne

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Unread post Sat Mar 20, 2010 3:51 pm

Re: Mistakes in Course Notes & HW Assignments

On Slide 24, gamma hat for DP2: I think the 3rd term should have dij_T not dotted
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Dan Negrut

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Unread post Sat Mar 20, 2010 4:32 pm

Re: Mistakes in Course Notes & HW Assignments

ME751Anne wrote:In HW9, I think you mean gamma_hat rather than just gamma.


change made and HW updated on the website.
thank you.
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Dan Negrut

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Unread post Sat Mar 20, 2010 4:38 pm

Re: Mistakes in Course Notes & HW Assignments

ME751Anne wrote:On slide 24, the gamma hat for DP1, I don't think a_j_T and a_i_T in the expressions should be dotted.


that is correct. thank you,
Dan
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Dan Negrut

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Unread post Sat Mar 20, 2010 4:44 pm

Re: Mistakes in Course Notes & HW Assignments

ME751Anne wrote:On Slide 24, gamma hat for DP2: I think the 3rd term should have dij_T not dotted


that is correct too.  I made the corrections and uploaded a more healthy version of that slide (when i first typed that slide in LaTeX i had seven mistakes in it; turns out there were more than seven :) ).
Thank you, Anne.
Dan
Last edited by Anonymous on Sat Mar 20, 2010 4:47 pm, edited 1 time in total.
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ME751Anne

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Unread post Tue Mar 30, 2010 4:27 pm

Re: Mistakes in Course Notes & HW Assignments

on the newest slides, on slide 4, you have tn for the forward Euler. Shouldn't this be t(n-1)?
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Dan Negrut

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Unread post Wed Mar 31, 2010 7:28 am

Re: Mistakes in Course Notes & HW Assignments

ME751Anne wrote:on the newest slides, on slide 4, you have tn for the forward Euler. Shouldn't this be t(n-1)?


Very good point, Anne.  I will correct the slides.
Thank you,
Dan
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ME751Chris

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Unread post Wed Apr 07, 2010 1:31 am

Re: Mistakes in Course Notes & HW Assignments

Slide 15 from April 6th.  The correction should be added to the current time step since we use a -g...right?  In the previous slide it seems right...
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Dan Negrut

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Unread post Wed Apr 07, 2010 6:36 am

Re: Mistakes in Course Notes & HW Assignments

ME751Chris wrote:Slide 15 from April 6th.  The correction should be added to the current time step since we use a -g...right?  In the previous slide it seems right...


you're darn right.
thank you, Chris.
dan
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ME751Anne

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Unread post Wed Apr 07, 2010 9:43 am

Re: Mistakes in Course Notes & HW Assignments

I think there is a mistake in the handout on using BE with Newton Raphson (the handout with the alpha, beta problem). I think the (2,1) entry of the Jacobian should have a y_n term in the second expression.
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Dan Negrut

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Unread post Wed Apr 07, 2010 10:26 am

Re: Mistakes in Course Notes & HW Assignments

Anne, what slide is this?
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ME751Chris

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Unread post Wed Apr 07, 2010 10:57 am

Re: Mistakes in Course Notes & HW Assignments

ME751Anne wrote:I think there is a mistake in the handout on using BE with Newton Raphson (the handout with the alpha, beta problem). I think the (2,1) entry of the Jacobian should have a y_n term in the second expression.


The jacobian of page 2 in the pdf notes of the bEuler formulation, the 2,1 entry, second term should be h*B*y(n)*...that's what I have in my notes from class.
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ME751Chris

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Unread post Wed Apr 07, 2010 4:25 pm

Re: Mistakes in Course Notes & HW Assignments

kind of minute, but on 3/11, slide 22, second bullet point, I believe the the last term in each matrix should be 3nb instead of nb.
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adminSBEL

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Unread post Wed Apr 07, 2010 4:37 pm

Re: Mistakes in Course Notes & HW Assignments

ME751Chris wrote:kind of minute, but on 3/11, slide 22, second bullet point, I believe the the last term in each matrix should be 3nb instead of nb.


Chris - what's in slide 22 is good.  The last term, like n_{nb} means that this is the torque of the "nb" body; i.e., the last body.  Since each torque has three components, the overall length of the vector is 3nb.

let me know if this still sounds confusing.
dan
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