### Re: Mistakes in Course Notes & HW Assignments

Pointed out by Praveen and Makarand.

Thank you both.

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.

Pointed out by Praveen and Makarand.

Thank you both.

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.

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

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

change made and HW updated on the website.

thank you.

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

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.

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

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

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...

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

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.

Anne, what slide is this?

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.

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.

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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