@acer  Thank you very much for the detailed analysis of the situation with floats.

@Markiyan Hirnyk  Your example does not contradict anything. By default  Digits=10 so

is(4.=4.+10^(-20));

              true

Or use quotes:

plot( 'myproc(300,V)', V=0.1..0.9 );

Maximize(
'myproc(300,v)',
v=0.00001..0.99999
);

@acer   Thanks for  Explore ! This tool is very interesting. I did not know (as well as Rouben) about it.

@mathnoob1  For clarity, you can make all the different colors: text in black (by default), 2d-math input in red, output in blue (by default).

Example:

and so on.

See the solution here

@abbeykabir  The error in the line   y[j]:= y + h*fxy(a,b):

The name of indexed variable  y[j]  coincides with formal parameter  y
 

@smith_alpha   

f:=x^2*exp(-1.2*x);

M:=[maximize(f, x=0..100, location)];

a:=M:  L:=[2,1,1,1,2]:

for i in L do

a:=op(i, a);

od;

Of course, all these steps I'm doing in the mind.

@Markiyan Hirnyk  http://dxdy.ru/topic19074.html

@Markiyan Hirnyk  I think that your moralism out of place in our community. You are not a teacher at school and I'm not your pupil.

@Markiyan Hirnyk  See links on request  "задача о жуках в вершинах квадрата"  here

@smith_alpha 

1) op  command extracts operands from an expression. In syntax  op(list, e)  the list of integers indicates positions of operands at increasing nesting levels of an expression. See help for details.

2) Since your maximum is reached at a critical point, here are two more ways to solve the problem:

a:=eval(x, solve({diff(f,x)=0, diff(f,x,x)<0}));  # Direct short solution

or

extrema(f, {}, x, 's');  # From all the extrema values we select the point in which the maximum value

s;

a:=max(map(rhs@op, s));

It is interesting that purely visually in the output, they are indistinguishable. But Maple distinguishes them:

Pi, pi;

evalf(%);

@Markiyan Hirnyk  What does the acronym  SCR?

@Carl Love  Thank you for the good advice!