@Kitonum 

Would you please tell me why "," that is comma, at the last of "evalindets(Expr, 'function', t->op(0, t)), " in yor code,
cannot be replaced with ";" that is semicolon?

@Scot Gould 

Sorry. As the description of two commands are the same other than the outcome of
examples there, I thought they were the same. But, they are different.
See below.

plot(-(x+2)*(x+1)*(x-1),x=-2.1..2.1);
evalf(ExtremePoints(-(x+2)*(x+1)*(x-1),x=-3..3));
evalf(CriticalPoints(-(x+2)*(x+1)*(x-1),x=-3..3));

The output of ExtremePoints contains the end points x=-3..3, and
that of CriticalPoints does not.
So, in the case of the original question, CriticalPoints, which is Markiyan's answer, is more appropriate.
 

@Scot Gould 

I think that I wrote the above anwer after reading mskalsi's question of
"I am interested in derivative. In fact my aim is to extract Maxima and Minima from plot."

As for the extreme points, the following which is  almost the same
as that of Markiyan Hirnyk, just different in the name, is my answer.

f:=0.012981+0.080285*cos(0.9519256799*x)+0.041370*cos(1.903851360*x)+
0.035690*cos(2.855777040*x)+0.000147*cos(3.807702720*x):

Student[Calculus1]:-ExtremePoints(f,x);
I don't know why two commands with the same function exist.
And, as for maximum of f,

Optimization[Maximize](f, x = -6 .. 6);
works.

Can you explain the meaning of your A_i B_{i j} = \sum_{i=1}^3 A_i B_{i j} in more detail with some conclete example?
And, please explain the meaning of your second expression of A_{i j} B_{m j} C_{i m} V_k.
From where did ,for example, the expression A_{i j} come from?

a:=-0.2126639710e-354*(-29.5456666e356*exp(-4.150297840*y)*cos(3.641492391*y));
       628.3298785 exp(-4.150297840 y) cos(3.641492391 y)
evalf(Int(a,y=-b..b));
    /b                                                        
   |                                                          
   |     628.3298785 exp(-4.150297840 y) cos(3.641492391 y) dy
   |                                                          
  /-1. b                                                      

The output of evalf(Int(a,y=-b..b)) cannot be evaluated to be numeric, because b is just a variable.

Maple 2016 is not assumed to work on Sierra.

http://www.maplesoft.com/products/system_requirements.aspx#maple

You have to wait for the next version of maple for its using in the Sierra.

@leonardofernandez 

Though this is not an answer to your question, I changed my setting of maple 2016 and mac osx 10.11.6
to Spanish setting, then I did what you did to get that eps.
As I cannot append the file with the extention eps to this site, I changed that extention to txt.
Can you open that file with double clicking after changing that extention of txt to eps?

By the way, I could open that file with my environment.

prueba.txt

@Rouben Rostamian  
Please write more explicitly for the function g.

Doesn't you file have the name containing " i ", but the dot of i is not dot but comma?
And, does the same error occur even if you change that i specific to Spanish to the usual i in English?
Containing such as umlaut seems to induce some errors, which has  been reported in Mapleprimes.

Is there that Prefix command anywhere in Maple?

@AmusingYeti 

Thank you for telling me convert command. It can change eps to pdf as well as png, very convenient.

I don't have any illustrator or such sort, so I used Preview of Apple, and Skim, which is like acrobat reader,
And, though Preview converts eps file to pdf, it can open that pdf, and for Skim, it can open eps itself.

Edit of menubar-> undo brings you to before you delete something.

Or, you can execute the original command again and get the original answer.

@nm
@ThU 

Thank you for your reply. And, thank you for your explanation, ThU.

@nm 

Surely, without simplify, the graph does not appear.
Please teach me why simplify is necessary in this case.