text: map2...
  map2(select,a->(a[1]>0),p)
  convert?...
  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)
  center not an option...
  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).
  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]]:
  Matrixfind(1,M,N)
  [0.8, 0.6, 0.5, 2.3, 2.6]
  Matrixfind(2,M,N)
  [0.4, 0.3, 0.8]
  Document mode vs worksheet mode...
  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.
  remove sets...
  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.
  formulas in Excel to Maple...
  Maple can't load the underlying formulas in the cells from excel, only the visualized data.
  In the short period of time I have. You can use textplot with plot to get the curves in your plot. I think it's possible to get the same linestyle in a legend, maybe not actually use the legend option but use a plot within a plot as the legend.
  To get you started on a solution, combine textplot with plot. Here's an example
  point1 := {seq([(1/3)*x, -((1/3)*x-3)^2+4, "Δ"], x = 0 .. 15)}:
  a := textplot(point1):
  b := plot(-(x-3)^2+4, x = 0 .. 5):
  It may be available onsite at university computer labs for free use for students. But otherwise the full version student version is a discounted price for use at home.
  Expand then simplify...
  First expand and then simplify will work.
  simplify(expand( beta^(1/2)*(1+beta^(1/2))/(beta+beta^(1/2)) )
  randcomb([-1,1],1)
  Use display to join plots. You didn't mention what kind of straight line. If you set your plot to a, and for example set one of these to b