Kitonum

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These are answers submitted by Kitonum

 

plots:-intersectplot(x^2+y^2+z^2=1,x+y+z=0, x=-1..1, y=-1..1, z=-1..1);

This behavior seems like a bug. Here is a workaround:

sol_2:=subs(_C1=C[1], sol_1):
simplify(eval(ode, [sol_2, sol_2^2])) ;
                               
 0=0

restart;
A:=((y*sqrt(3) + 3)*sqrt(3))/(6*sqrt(y^2 + 1));
B:=(y + sqrt(3))/(2*sqrt(y^2 + 1));
	
expand(arctanh(A)-arctanh(B));

Output:        
                              0


 

I understood the  "identify"  word as the need to collect identical objects into separate groups (lists). The code below does this:

restart;
Eq1:=5.09295817894067*`τu`[1, 1]-30.5577490736439*`τu`[2, 1]+178.253536262923*`τu`[3, 1]-30.5577490736439*`τu`[1, 2]+183.346494441862*`τu`[2, 2]-1069.52121757753*`τu`[3, 2]+178.253536262923*`τu`[1, 3]-1069.52121757753*`τu`[2, 3]+6238.87376920228*`τu`[3, 3]:
Eq2:=5.09295817894067*`τu`[1, 1]+10.1859163578814*`τu`[2, 1]+15.2788745368241*`τu`[3, 1]-30.5577490736439*`τu`[1, 2]-61.1154981472883*`τu`[2, 2]-91.6732472209439*`τu`[3, 2]+178.253536262923*`τu`[1, 3]+356.507072525849*`τu`[2, 3]+534.760608788841*`τu`[3, 3]-3/7:
Eq3:=5.09295817894067*`τu`[1, 1]-30.5577490736439*`τu`[2, 1]+178.253536262923*`τu`[3, 1]+10.1859163578814*`τu`[1, 2]-61.1154981472883*`τu`[2, 2]+356.507072525849*`τu`[3, 2]+15.2788745368241*`τu`[1, 3]-91.6732472209439*`τu`[2, 3]+534.760608788841*`τu`[3, 3]-9/7:
Eq4:=5.09295817894067*`τu`[1, 1]+10.1859163578814*`τu`[2, 1]+15.2788745368241*`τu`[3, 1]+10.1859163578814*`τu`[1, 2]+20.3718327157631*`τu`[2, 2]+30.5577490736484*`τu`[3, 2]+15.2788745368241*`τu`[1, 3]+30.5577490736484*`τu`[2, 3]+45.8366236104784*`τu`[3, 3]-12/7:
Eq5:=5.09295817894067*`τu`[1, 1]-30.5577490736439*`τu`[2, 1]+178.253536262923*`τu`[3, 1]+50.9295817894067*`τu`[1, 2]-305.577490736439*`τu`[2, 2]+1782.53536262923*`τu`[3, 2]+504.202859715131*`τu`[1, 3]-3025.21715829077*`τu`[2, 3]+17647.1000900295*`τu`[3, 3]-18/7:
Eq6:=5.09295817894067*`τu`[1, 1]+10.1859163578814*`τu`[2, 1]+15.2788745368241*`τu`[3, 1]+50.9295817894067*`τu`[1, 2]+101.859163578814*`τu`[2, 2]+152.788745368241*`τu`[3, 2]+504.202859715131*`τu`[1, 3]+1008.40571943027*`τu`[2, 3]+1512.60857914560*`τu`[3, 3]-3:
Eq7:=5.09295817894067*`τu`[1, 1]+10.1859163578814*`τu`[2, 1]+15.2788745368241*`τu`[3, 1]-30.5577490736439*`τu`[1, 2]-61.1154981472883*`τu`[2, 2]-91.6732472209439*`τu`[3, 2]+178.253536262923*`τu`[1, 3]+356.507072525849*`τu`[2, 3]+534.760608788841*`τu`[3, 3]-3/7:
Eq8:=5.09295817894067*`τu`[1, 1]+10.1859163578814*`τu`[2, 1]+15.2788745368241*`τu`[3, 1]+10.1859163578814*`τu`[1, 2]+20.3718327157631*`τu`[2, 2]+30.5577490736484*`τu`[3, 2]+15.2788745368241*`τu`[1, 3]+30.5577490736484*`τu`[2, 3]+45.8366236104784*`τu`[3, 3]-12/7:
Eq9:=41.7622570673196*`τu`[3, 1]+41.7622570673196*`τu`[1, 3]+15.2788745368220*`τu`[1, 1]+83.5245141346398*`τu`[2, 3]+30.5577490736443*`τu`[2, 1]+113.063671572516*`τu`[3, 3]+83.5245141346398*`τu`[3, 2]+30.5577490736443*`τu`[1, 2]+61.1154981472892*`τu`[2, 2]:

S:=[seq([i,Eq||i], i=1..9)];
S1:=[ListTools:-Categorize((u,v)->u[2]=v[2], S)];
map(t->op~(1,t), S1);
op(select(t->nops(t)>1, %));

The final result:     
                                    [2, 7], [4, 8]


If you just need to remove duplicates, then do

{seq(Eq||i, i=1..9)};

 

If we divide the total area of all the necessary pieces of plywood into the area of 1 standard plywood sheet  48*96=4608, we get about 2.56. Thus, at least 3 standard sheets are required. I just cut out proportional sized pieces of paper and in 10 minutes I found the right solution. Thus, 3 standard sheets are needed. All calculations and visualization are below. For ease of identification, pieces of the same size are painted in the same color. All sizes are in inches.

> 

restart;

> 

4 - "40.625 x 20" - green
2 - "36 x 20" - blue
2 - "34.75 x 20" - khaki
3 - "33.75 x 12" - cyan
6 - "18.825 x 12" - red
3 - "32.5 x 12" - pink
3 - "33.75 x 19.5" - gold

> 

S[0]:=48*96; S[1]:=40.625*20; S[2]:=36*20; S[3]:=34.75*20; S[4]:=33.75*12; S[5]:=18.825*12; S[6]:=32.5*12; S[7]:=33.75*19.5;
L:=[4,2,2,3,6,3,3];
add(L[i]*S[i], i=1..7)/S[0];

4608

 

812.500

 

720

 

695.00

 

405.00

 

225.900

 

390.0

 

658.125

 

[4, 2, 2, 3, 6, 3, 3]

 

2.559629991

(1)


Code for a visualization

> 

with(plottools): with(plots):
Colors:=[green,blue,khaki,cyan,red,pink,gold,yellow]:

A1:=rectangle([0,20],[40.625,0], color=Colors[1]):
A2:=rectangle([0,20+20],[40.625,20], color=Colors[1]):
A3:=rectangle([0,20+40],[40.625,40], color=Colors[1]):
A4:=rectangle([0,20+60],[40.625,60], color=Colors[1]):
A5:=rectangle([0,20*4+12],[33.75,0], color=Colors[4]):
A:=polygon([[40.625,0],[48,0],[48,96],[0,96],[0,92],[33.75,92],[33.75,80],[40.625,80]], color=Colors[8]):
T1:=textplot([[20,10,"40.625 x 20"],[20,30,"40.625 x 20"],[20,50,"40.625 x 20"],[20,70,"40.625 x 20"],[17,85,"33.75 x 12"]], font=[times,14]):
A11:=display(seq(A||k,k=1..5),A,T1):

B1:=rectangle([0,34.75],[20,0], color=Colors[3]):
B2:=rectangle([20,34.75],[32,1], color=Colors[4]):
B3:=rectangle([32,34.75],[44,1], color=Colors[4]):
B4:=rectangle([0,34.75+33.75],[19.5,34.75], color=Colors[7]):
B5:=rectangle([19.5,34.75+33.75],[19.5*2,34.75], color=Colors[7]):
B6:=rectangle([0,34.75+33.75+19.5],[33.75,34.75+33.75], color=Colors[7]):
B7:=rectangle([33.75,34.75+33.75+18.825],[33.75+12,34.75+33.75], color=Colors[5]):
B:=polygon([[20,0],[48,0],[48,96],[0,96],[0,34.75+33.75+19.5],[33.75,34.75+33.75+19.5],[33.75,34.75+33.75+18.825],[33.75+12,34.75+33.75+18.825],[33.75+12,34.75+33.75],[19.5*2,34.75+33.75],[19.5*2,34.75],[44,34.75],[44,1],[20,1]], color=Colors[8]):
T2:=textplot([[70,18,"34.75 x 20",'rotation' = (1/2)*Pi],[70,50,"33.75 x 19.5",'rotation' = (1/2)*Pi],[85,50,"33.75 x 19.5",'rotation' = (1/2)*Pi],[77,80,"33.75 x 19.5"],[86,18,"33.75 x 12",'rotation' = (1/2)*Pi],[97,18,"33.75 x 12",'rotation' = (1/2)*Pi],[100,77,"18.825 x 12",'rotation' = (1/2)*Pi]], font=[times,14]):
B11:=display(translate(display(seq(B||k,k=1..7),B),60,0),T2):

C1:=rectangle([0,32.5],[12,0], color=Colors[6]):
C2:=translate(C1,12,0):
C3:=translate(C1,24,0):
C4:=rectangle([36,18.825],[48,0], color=Colors[5]):
C5:=seq(translate(C4,0,18.825*k), k=1..4):
C6:=rectangle([0,52.5],[36,32.5], color=Colors[2]):
C7:=translate(C6,0,20):
C8:=rectangle([0,92.5],[34.75,72.5], color=Colors[3]):
C:=polygon([[0,92.5],[34.75,92.5],[34.75,72.5],[36,72.5],[36,96-18.825*5],[48,96-18.825*5],[48,96],[0,96]], color=Colors[8]):
T3:=textplot([[126,16,"32.5 x 12",'rotation' = (1/2)*Pi],[138,16,"32.5 x 12",'rotation' = (1/2)*Pi],[150,16,"32.5 x 12",'rotation' = (1/2)*Pi],seq([164,9+18.825*k,"18.825 x 12",'rotation' = (1/2)*Pi],k=0..4),[138,42,"36 x 20"],[138,62,"36 x 20"],[138,84,"34.75 x 20"]], font=[times,14]):
C11:=display(translate(display(seq(C||k,k=1..8),C), 120,0),T3):

display(A11,B11,C11, scaling=constrained, size=[950,540], axes=none);

 

 
> 

 

                 

Plywood1.mw  

Use the  isolve  command for this:


 

eq1 := [isolve({2*m-5 < 0, -3*m <= 5})]

[{m = -1}, {m = 0}, {m = 1}, {m = 2}]

(1)

nops(eq1)

4

(2)

``

``

eq2 := [isolve({m-3 < 0, -m <= 6})]

[{m = -6}, {m = -5}, {m = -4}, {m = -3}, {m = -2}, {m = -1}, {m = 0}, {m = 1}, {m = 2}]

(3)

nops(eq2)

9

(4)

``

 

Addition. Unfortunately,  isolve  command is not effective enough and quite often (in more difficult situations) it does not cope with the task of finding integer points. On this occasion, look at these 2 posts:  https://www.mapleprimes.com/posts/202437-Integer-Points-In-Polyhedral-Regions  and  https://www.mapleprimes.com/posts/202542-Integer-Points-In-Curved-Regions

 

Download help_list_integer_equation_new.mw

This is the standard integer linear programming problem. See wiki  https://en.wikipedia.org/wiki/Cutting_stock_problem 

See also  How do I solve Cutting Stock Problem in Maple - MaplePrimes 

We project points  C  and  D  on the plane of the base of the cylinder. We get points  C'  and  D' . Obviously  ABC'D'  is a rectangle. For the origin we take the center of this rectangle, we direct the  x axis through the middle of  AB, and the  y axis through the middle of  BC' . Let  AB = a  and  C'B=b .  To find  a  and  b , we have a simple system of two equations with 2 unknowns. We solve it with Maple:

solve({a^2+b^2=6^2, b^2+2^2=a^2, a>0, b>0});

               {a = 2*5^(1/2),  b = 4}

Further finding the coordinates of all points is obvious.

If you want to enter those programmatically (without a palette directly from the keyboard) in 1D Input or 2D Input modes, then this can be done as in the examples below:

conjugate(a); 
`#mover(mi("a"),mo("~"))`;
`#mover(mi("a"),mo("&circ;"))`;
`#mover(mi("a"),mo("&rarr;"))`;

Output:
                                     

 

You can write even shorter with the same result:

restart;
f := (Pi*x+2*c+2*m)/(mu__c*S)+2*epsilon/(mu__a*S)+(Pi*x+2*c)/(mu__s*S);
int(1/f, x=0..w)   assuming positive;

You can simplify the final result a little:

combine(%) assuming positive;

 

I removed the double quotes and added 2 more options:

restart;
f:=x->1/x^2:
plot(f(x), x = -10 .. 10, thickness = 3, labels = ["", ""], tickmarks = [[4 = infinity, -4 = -infinity], [0]], view = [-6 .. 6, 0 .. 5], scaling = constrained, size = [900, 375]);

 

If you mean the  FunctionAdvisor  command then it appeared in Maple 9 in 2003. 
See  ?updates,v9

restart;
Sys:={x=a/(1+C^2)^(3/2), y=a*C^3/(1+C^2)^(3/2)}:
simplify(map(t->t^(2/3), Sys));
`+`(op(%));
applyop(simplify,2,%) assuming a>0, C>0;

                    


In fact, of course, the original set  {x=..., y=...}  does not coincide with the set  x^(2/3)+y^(2/3)=a^(2/3) , since for a chosen parameter  a  sign of  x  will always coincide with the sign of  a  (in my interpretation without the minus). However, under the conditions  a>0, C>0, x>=0, y>=0  these sets coincide.

Try

f:=(l::list)-> eval([y,y*z-x,-15*x*y-x*z-x],zip(`=`,[x,y,z],l));

f([1,2,3]);
                              
[2, 5, -34]


But why not just write

f:=(x,y,z)-> [y,y*z-x,-15*x*y-x*z-x];

f(1,2,3); 
                                
 [ 2,5,-34]  

  


                             

  

   

# Ellips x^2/a^2+y^2/b^2=1, a>b
# Circle x^2+y^2=a^2
# The ellipse is obtained by compressing the circle to the Ox axis with a coefficient k=b/a

a:=5: b:=3: k:=b/a:
F:=plottools:-transform((x,y)->[x,k*y]):
A:=plot([a*cos(t),a*sin(t), t=0..2*Pi], color=blue, thickness=2):
plots:-display(A, F(A));

 

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