Under Options->General. Uncheck it

try expanding it first so both sides have same structure?    evalb(a-a*b=expand(a*(1-b)))  now gives true.

Help says

The evalb command does not simplify expressions. It may return false for a relation that is true. In such a case, apply a simplification to the relation before using evalb.
 

In this case simplify() did not make it give true.

or you could just use is(a-a*b=a*(1-b)) gives true without the need to expand or simplify.

You can try adding some assumptions? for example

Download t2.mw

This works for me. 

restart;
f := 9*x^3 - 7*x^2*y + 8*x*y^2 - 6*y^3 + 3*x^2 - 3*x*y + 4*y^2 - 3*x + 9*y - 7;
fx:=diff(f,x);
fy:= diff(f,y);

ctpts:= solve({fx=0,fy=0},{x,y});
evalf(allvalues(ctpts))

{x = 0.04295586238 + 0.2689937615*I, y = 0.9924517251 + 0.1221355623*I}, {x = -0.1196978953, y = -0.5678259706}, {x = -0.2777747003, y = -0.6265224321}, {x = 0.04295586238 - 0.2689937615*I, y = 0.9924517251 - 0.1221355623*I}

I do not know how to add rules to the build in simplify command in Maple (It is possible to do this in Mathematica easily). May there is a way to do it in Maple in order to teach it a new "rule".  The standard simplify(expr,ln) did not do it.

For now you can do

expr:=(ln(-z*I + b) - ln(z*I + b));
I*simplify(log(exp(expr)))

I calculated 6 critical points :how to show them in the plot? 

restart;
f:=(x,y)->x^4-3*x^2-2*y^3+3*y+1/2*x*y; 
cp:=  solve( {diff(f(x,y),x)=0,diff(f(x,y),y)=0}, {x,y});
cp:=  evalf(allvalues(cp));
pts:= map(X->eval([x,y],X),[cp]);
pts:=map(X->[op(X),f(X[1],X[2])],pts);
plots:-display([plot3d(f),plots:-pointplot3d(pts,'color'='red','symbol'='solidcircle','symbolsize'=15)])

Using the view point used by others, we get

plots:-display([plot3d(f(x,y),x=-2..2,y=-2..2, view=-6..6),plots:-pointplot3d(pts,'color'='red','symbol'='solidcircle','symbolsize'=15)])

How to make table out of this list.CriticalPoints. for easy reading.?

<<'x'|'y'|'z'>,Matrix(pts)>

would it not be better to just use collect? Then the result is automatically sorted by L[n], but it is also collected, which is easier to read also.

result:= expand(((673*L[13] - 485*L[14] - 176*L[15])*h^2 - 90*(L[13] - (13*L[14])/15 - (2*L[14])/15)*x*h)/(12*h^3));
collect(result,indets(result,'indexed'))

Alternatively, a way to factorize  into  could do the trick.

restart;
expr:=a*x+6*x^2-10;
tmp:=select(has,expr,x);
factor(tmp)+expr-tmp;

I am not sure if is possible to write Q3 = gamma*Q1 + (1-gamma)*Q2 

Maple says it is not possible. You can try simplify with side relations

restart;
Q3 := 1/(v)*(    v*pi-  (   (1-alpha*gamma) *pi * r[0]  - (1-pi)*B*alpha  + (gamma*pi + (1-pi)*h)    )   );
eqs:={ 1/v *(  v*pi    -  (   h - (1-pi)*B   )      )=Q2,1/v*(   v*pi     - (   pi*r[0]+ (1-pi)*h  )   )=Q1};
simplify(Q3,eqs);

I have not used this command before myself in Maple, but may this is what you want

plots:-conformal(exp(2*z), z=0..1+I);

may be you can use the definition of concave function. From Wiki

 A differentiable function f is (strictly) concave on an interval if and only if its derivative function f ′ is (strictly) monotonically decreasing on that interval, that is, a concave function has a non-increasing (decreasing) slope.^[3][4]

So just need one counter example. This is your g(x) function which is increasing and concave function g:=x-exp(-x). 

If you plot the derivative of   (2*x+5)*g(x), you will see is not concave.

Why would you load LinearAlgebra and then at same time make call to linalg:- ?

    Important: The linalg package has been deprecated. Use the superseding packages, LinearAlgebra

if you remove that then it works. It might have to do with how linalg works. I do dot know for sure, but this works.

To multiply these matrices/vectors, just use the dot. So intead of what you had

          linalg:-multiply(Ts_sksul, XCin)

you can just do

         Ts_sksul.XCin

fixed.mw

diff(x^n,x) does not equal n*x^(n-1), but rather 0 if n=1

you probably meant rather 1, and not rather 0..

This seems like a bug to me

it is not a bug. all CAS systems work on a general expressions, not specific values. 

To get derivative for specific n you need to give specific value for n.

Maple by default uses 10 decimal points to display real numbers.

This works for 2021.1 on windows 10, using worksheet interface

restart;
interface(typesetting=extended);
Typesetting:-Settings(striptrailing=true);
V := 4;
K := 16.56;
H := 0.5;
q1 := diff(y[1](x), x) = V*y[2](x)/H - K*y[1](x)/H;

Or you could do

restart;
V := 4;
K := 16.56;
H := 0.5;
q1 := diff(y[1](x), x) = V*y[2](x)/H - K*y[1](x)/H:
convert(q1,rational)

See this post for reference. How-To-Delete-Zeros-After-Decimal-Point

btw, why are using evalf for? Your numbers already real.

When expression is   A+B then operands are A and B. And select selects operand which has what you wanted. So if the expression is t*u[1,1,1]*u[1,1,1,2]+2 then A=t*u[1,1,1]*u[1,1,1,2] and B=2, that is why it returned A.

When the input is t*u[1,1,1]*u[1,1,1,2] then expression is A*B*C and each one is now an operand. So A=t, B=u[1,1,1] and C=u[1,1,1,2] and that is why select now returned only u[1,1,1]

One way could be to do 

LT:=proc(expr, term)
 if type(expr,`+`) or nops(expr)=1 or expr=term then
    select(has, expr, term);
 elif type(expr,`*`) then
      if has(expr,term) then
          return expr;
      else
          return NULL;
      fi;
 else
     error "not expression?";
 fi;
end proc;

And now it works for both cases