It appears they used mathematica to build the olympic Velodrom http://www.wolfram.com/customer-stories/key-features-of-mathematica-used-for-the-olympic-velodrome.html

They mention Fresnel integrals, and then it looks like they used an interpolation function (I think that function does what we succeded in doing with Maple back in 2011 - Can we get an exact curve fitting line) to get very good estimates of values without consuming large amounts of calculation time.  Looking further into it I find Track transition curve  which mentions a Euler sprial for the "easement" curve. 

Sorry, that's all I have for you now. 

See the writeto command.  That might be what you're looking for.

Wait, the derivative wrt a derivative?  I think the Physics package diff will do what you want it to do.

with(Physics):

Your dL/d(dq1) will be diff(L,diff(q1(t),t))

and then simply what you had in your original " d (dL/d(dq1)) dt  "  will then just be diff(diff(L,diff(q1(t),t)),t)

I think that is what you are asking.

See here for some insight

https://www.mapleprimes.com/questions/200606-How-To-Write-Procedures-In-MAPLE-To

For display purposes you could do

As Carl said, your request doesn't make much sense (removing 1 element at a time from a sorted list doesn't change the order) ... and removing 19 0's - must be a mistake on your part.  Nonetheless, you could use remove has

for i from 1 to nops(b) do #loop over the number of elements in list b
  a:=remove(has,a,b[i]); #new list of elements in a with element b[i] removed.
end do:

Another way

map2(select,a->(a[1]>0),p)

If you mean the other value, Maple views numbers in radians but using convert you can go back and forth between degrees and radians ie.  

convert(Pi/4,degrees);

convert(90*degrees,radians);

You could also use readdata

readdata("filename",string,2)

remove center from your align commands.  center is not one of the options.

I don't think a seperate package will be developed.  It will be in the works for the Physics package.  But actually I think ecterrab mentioned something to that effect being started at the end of 2016 (not quite 5 years ago). 

Another way,

Matrixfind:=proc(a,b,c)
  local g,h,k:
  uses ListTools:
  g:=[SearchAll(a,Flatten(convert(b,listlist)))]:
  h:=[]:
  for k in g do
    h:=[op(h),Flatten(convert(c,listlist))[k]]:
  end do:
  h;
end proc:

Matrixfind(1,M,N)
               [0.8, 0.6, 0.5, 2.3, 2.6]

Matrixfind(2,M,N)
              [0.4, 0.3, 0.8]

In document mode it's difficult to associate equations with correct labels.  Some time ago I mentioned something about plots within a document mode messing up underlying Labels so the labels shown are not what DocumentTools Retrieve would retrieve. 

If changes have taken place in a separate document they won't automatically update the linked document I believe until it is re-executed.

Ok, correct me if I'm wrong but it sounds like you create a particular worksheet with particular formatting applied to the fonts.  Then when you open the worksheet at some other time it has all changed. 

It could be that the scripts you changed your fonts to have all been defaulted somehow.  Are you not saving your changed fonts?  This may not be the reason I'm only offering a possible cause.

So if you want to remove a set with the condition k[d2]=k[d1] because it's not allowed then here's one way

seq(`if`(has(Sa1[i], k[d2] = k[d1]), 0, Sa1[i]), i = 1 .. nops(Sa1))
 

Conversly and probably a better way by using Carl Loves way using remove(s-> in your other question to use some way here, but I am unable to get the proper order of commands.