It is shorter and faster to use  plot  command for this (without calling  plots  package):

L1:=[seq(j, j=1..10)];
L2:=[seq(j^2, j=1..10)];
plot(L1, L2, style=point, symbol=solidcircle, symbolsize=20);
# Or
plot(L2, L1, style=point, symbol=solidcircle, symbolsize=20);

 #  If you omit  style=point  option, then (by default) Maple draws a polyline that connects these points:

plot(L1, L2);
 

Your system has no solutions, since we have

dsolve({diff(x(t), t) = y(t), diff(y(t), t) = -x(t), x(0) = 0, y(0) = 1});
evalf([(D(sin))(8), (D(-cos))(8)]);
                                {x(t) = sin(t), y(t) = cos(t)}
                          [-0.1455000338, -0.9893582466]
 

You must impose the condition of touching the circles  C4  and  C2 : the distance between the centers is equal to the sum of the radii. Here is the solution:

restart; with(geometry):

x0 := (3+1/2)/2;
x1 := x0; y1 := x0 + (1+1/4);
point(P1, x1, y1); ## center of the circle
circle(C2, [P1, x0]);

x3 := (3+1/2)/2-(3/4+20/1000)/2-1/2; y3 := 1+1/4; evalf([x3, y3]);

point(P2, x3, 0); point(P3, x3, y3);
line(L1, [P2, P3]);
intersection(I1, L1, C2);
for s in I1 do print(evalf(coordinates(s))) end do;
tr := 1/8;  ## tool radius, radius of C4

x4 := x3 - tr;

point(P4, x4, y4);
circle(C4, [P4, tr]);
Equation(C4,[x,y]);
distance(P4,P1);
solve({%=tr+x1,y4<y1});
point(P4,x4,eval(y4,%));
circle(C4, [P4, tr]);
intersection(I2, C2, C4);  # The point of touching the circles  C4  and  C2
detail(I2);
draw([L1,C2,C4], view=[0..4,0..5], axes=normal);

I usually prefer to use lists or vectors; over them it is more convenient to make various arithmetic manipulations:

N:=10:
Y := [seq(i^2, i=1 .. N)];   # This is the list
DY := Y[3 .. N] - Y[1 .. N-2];  # This list also

# or the same, but slightly longer:

DY := [seq(Y[n+1]-Y[n-1], n=2..N-1)];

sqrt((360-alpha[1]-3*alpha[2])/``(720/Pi^2*(cos(Pi*alpha[1]/180)+cos(Pi*alpha[2]/180))^2)-1);

#  or

sqrt((360-alpha[1]-3*alpha[2])/(``(720/Pi^2)*(cos(Pi*alpha[1]/180)+cos(Pi*alpha[2]/180))^2)-1);

Maple can not solve your equation  deq=3  for  x , since the explicit dependence of  y(x)  is unknown. Here is a workaround:

restart:
eq:=4*x^2+2*y(x)^2=32.5625:
deq:=solve(  diff(eq,x), diff(y(x),x) );
deq=3;
y(x)=solve(deq=3, y(x));
x=solve(subs(y(x)=y, deq=3), x);

RootOf(2*_Z+3*y(_Z))  is a formal representation of the root of the equation  2*_Z+3*y(_Z)=0  with respect to  _Z

I corrected all the syntax errors. We see that the integrand is actually a scalar function.  But Maple does not cope with this integral even for finite intervals. I think that the reason is in a large number of parameters (8 parameters).

You can try to calculate your integral by specifying the values of these parameters.

Edit.

Download Integration-Vec-Example_new.mw

restart; 
with(Physics):
Setup(mathematicalnotation = true);                
Setup(signature = `-+++`);                    
Coordinates(M = [t, rho, z, phi]);
ds2 := -exp(2*psi(rho, z))*dt^2+exp(2*gamma(rho, z)-2*psi(rho, z))*(drho^2+dz^2)+exp(-2*psi(rho, z))*(rho^2)*(dphi^2);  
Setup(metric = ds2);

Download subs.mw

You do not need  Logic  package for this:

a:=[false$4,true$4];
b:=[false$2,true$2,false$2,true$2];
c:=[seq(op([false,true]),i=1..4)];
A:=plot(piecewise(seq(op([x>n-1 and x<n,`if`(a[n]=false,0+7,1+7)]), n=1..8), undefined), x=0..8):
B:=plot(piecewise(seq(op([x>n-1 and x<n,`if`(b[n]=false,0+5,1+5)]), n=1..8), undefined), x=0..8):
C:=plot(piecewise(seq(op([x>n-1 and x<n,`if`(c[n]=false,0+3,1+3)]), n=1..8), undefined), x=0..8):
F:=plot(piecewise(seq(op([x>n-1 and x<n,`if`((a[n] and b[n] or c[n])=false,0+1,1+1)]), n=1..8),undefined), x=0..8, thickness=3):
T:=plots:-textplot([[-0.5,1.5,"F"],[-0.5,3.5,"c"],[-0.5,5.5,"b"],[-0.5,7.5,"a"]], font=[times,bold,16]):
plots:-display(A,B,C,F,T, view=[-0.7..8,0..8], tickmarks=[default,[seq(op([k=0,k+1=1]), k=1..7,2)]], labels=[``,``], scaling=constrained);

This post  https://www.mapleprimes.com/posts/207840-Combinations-Of-Multiple-Animations  will be interesting for you.

It works in Maple 2015.2:

restart;
with(plots):
A:=animate(plot, [[cos(t), sin(t), t=0..a]], a = 0 .. 2*Pi,  frames = 50):
B:=animate(pointplot, [[t,sin(t)], color = blue, symbol = circle, symbolsize = 18], t = 0 .. 2*Pi, frames=50, background = plot(sin(x), x = 0 .. 2*Pi)):
display([A, B], scaling = constrained, size=[1000,300]);

Addition. For those who like more compact codes, this animation can be written in one line, calling only  animate  command from  plots  package:

restart;
plots:-animate(plot, [[[cos(t), sin(t), t=0..a],[[a,sin(a)]]],style=[line,point],color = [RGB(0.47,0.,0.055),blue],symbol = circle, symbolsize = 18], a = 0 .. 2*Pi,  frames = 50,background = plot(sin(x), x = 0 .. 2*Pi), scaling=constrained, size=[1000,300]);

The final result:

See corrected file for details

how_to_draw_the_dashline_part_new.mw

Use  solve  instead of  simplify :

solve(F*R=(1/2*M*R^2)*(a/R), F);

restart; 
with(PDEtools):
umain := 1-exp(-y)+sum(A^i*u[i](y, z), i = 1 .. 5);
vmain := -1+sum(A^i*v[i](y, z), i = 1 .. 5);
wmain := sum(A^i*w[i](y, z), i = 1 .. 5);
pde[main] := diff(vmain, y)+diff(wmain, z);
pde[main[2]] := vmain*(diff(wmain, y))+wmain*(diff(wmain, z))-(diff(wmain, y$2));

sys[1] := [A^i*coeff(pde[main[2]], A) = 0, w[1](0, z) = sin(z), w[1](infinity, z) = 0];

for i from 2 to 5 do pde[i] := A^i*coeff(pde[main[2]], A^i) = 0; sys[i] := [pde[i], w[i](0, z) = 0, w[i](infinity, z) = 0] end do;

sol:=pdsolve(sys[1]);
w[1] := unapply(eval(w[1](y,z), sol), y,z);

# Examples of use
w[1](y, z);
w[1](1, 2);
plot3d(w[1], 0..1, 0..Pi);

Here is the solution with your data:

The code in 1d-math:

restart; 
rho := phi->chi/(1-e*cos(2*phi)):
e := 0.29:
chi := 0.5:
L := phi->Int(sqrt(rho(t)^2+(diff(rho(t), t))^2), t = 0 .. phi): 
plot(L(phi), phi = 0 .. 2*Pi); 
evalf(L(4)); 
evalf(L(5)); 
phi = fsolve(L(phi) = 50); 
plot(rho(phi), phi = 0 .. 2*Pi, coords = polar, scaling = constrained);
 

Download probléma_new.mw  # The code in 2d-math