Hi!

I am using solve() to solve a system of equations. Fortunately, the system is linear. Since it has more than 700 variables and more than 300 equations, I actually don't know if the solution exists.

I called solve() to solve the problem, and the solution I got indicates that all the variables are free variables. (That is, the solution is given as x_k = x_k for all variables.) Obviously, my system is not homogeneous, and 0 is not a solution to my problem. (I plugged in 0 and verified it.)

Since all the coefficients to my system are fractions, so I suppose the solve() function is using some symbolic algorithms? I don't know why this happens. Does this mean there is no solution to my system?

Thanks!

William

Hello. I have a question on plotting discrete time plot. When I try to plot the equation below I get an error. Can't figure out where is the problem. If for example I choose for vector A () there is no error. I would appreciate your help.

Error, invalid input: DynamicSystems:-DiscretePlot expects its 2nd argument, v2, to be of type {realcons, list(extended_numeric), ('Vector')(extended_numeric)}, but received Vector(4, {(1) = 1+sin(1), (2) = 1+sin(2), (3) = 1+sin(3), (4) = 1+sin(4)})

Regards,

Tadej

test_sections.mw

Hi, I'm getting some unusual behaviour between the Explore() command / graphs and collapsed sections, as exemplified in the attached (linked) worksheet.  I'm trying to develop some worksheets with several sections where some of the sections have an explore() graph in them.  To keep things simple, I'd like some sections to be collapsed with the graphs hidden (and remain collapsed: View - Section - Autoexpanding - Uncheck) when the worksheet is evaluated.  In the attached, the section remains collapsed, so does the normal graph, but the explore "graph" gets published outside the collapsed section and when there is other information on the worksheet, the explore window appears almost randomly.

So is there any way to ensure the explore graph remains inside the collapsed section?

Sorry for the slightly longwinded explanation :-)

Thanks,

Maple:

how exp into ?

exp2: 

into

Help

v := x -> `if`(x::numeric, x^2, 'procname(args)'):
u := x -> `if`(x::numeric, x^2, 'procname(args)'):

Optimization:-NLPSolve(v(x), {-1 <= x, x <= 1});
Error, (in Optimization:-NLPSolve) unsupported type of index, HFloat(1.0)

Optimization:-NLPSolve(u(x), {-1 <= x, x <= 1});
      [1.83670992315982423*10^(-40), [x = -1.35525271560688*10^(-20)]]

u and v are identical.

f := proc(x, rec := true)
  if rec then Optimization:-NLPSolve(2, y -> (y -~ 1/4).(y -~ 1/4), [], [<-1, -1>, <1, 1>],
    maximize = false) end if;
  (x -~ 1/4).(x -~ 1/4)
end proc:

fgrad := proc(x, g) g[1 .. 2] := 2*~(x -~ 1/4) end proc:

Optimization:-NLPSolve(2, f, [], [<-1, -1>, <1, 1>],
  maximize = false, objectivegradient = fgrad);
Warning, no iterations performed as initial point satisfies first-order conditions
        [0.125000000000000000, Vector[column](2, [0., 0.])]


Optimization:-NLPSolve(2, x -> f(x, false), [],  [<-1, -1>, <1, 1>],
  maximize = false, objectivegradient = fgrad);
        [0., Vector[column](2, [.250000000000000, .250000000000000])]

The inner NLPSolve doesn't do anything, except it breaks the outer NLPSolve.

Is is possible to tell the latex output what to do if it finds a symbol?

Suppose I have the following expression:

O3^2 + k_O3NO

The normal latex output just takes it as it is and also translates k_O3NO to k_O3NO with the underscore.

I however want it to read (latex notation in math mode)

\left[ \text{O}_3 \right]^2 + k_{\text{O}_3\text{NO}}

So is that possible without changing everything manually?

edit: Just as a remark, the output at the moment for this expression reads

{{\it O3}}^{2}+{\it k\_O3NO}

and is kinda awful if compiled in latex...

Is it also possible for maple to latex realizing where a line-break is necessary?

# Bending Moment Envelope Curve for Isostatic Two-Span Beam

restart:

with(plots):

with(Optimization):
PD:= proc (L1, L2, L3, N)

local l, R, Y, M, M1, M2, V:

R[1]:= piecewise(x <= L1, (L1-x)/L1, 0):

l[1]:=L1:

l[2]:=L2:

l[3]:=L3:

solve([add(R[i], i = 1 .. 3) = 1, add(R[j]*add(l[i], i = 1 .. j), j = 2 .. 3) = x], [R[2], R[3]]):

R[2]:=rhs(%[1][1]):

R[3]:= rhs(`%%`[1][2]):

M1:=piecewise(y <= add(l[i], i = 1 .. 2), R[1]*y, `and`(add(l[i], i = 1 .. 2) < y, y <= add(l[i], i = 1 .. 3)), R[1]*y+R[2]*(y-add(l[i], i = 1 .. 2))):

M2:=piecewise(y <= x, 0, x-y):

for Y to N do eval(M1+M2, y = Y*add(l[j], j = 1 .. 3)/N):

M[Y]:=Maximize(abs(%),x=0..add(l[j],j=1..3))[1]

end do:

pointplot(`<,>`(seq(i*add(l[j], j = 1 .. 3)/N, i = 1 .. N)), `<,>`(seq(M[i], i = 1 .. N)), color = red, symbol = asterisk):

display(%, axis = [gridlines = [10, color = black]], size = [700, "golden"], axesfont = [Times, 16])

end proc:

Hello everyone,

I am trying to solve a differential equation using dsolve command for laplace transform.

In Equation 2, a is a constant and x(t), b(t), u(t) are functions.

What is the "_U1" in the output (4)? Is it because I have defined x(t), b(t), u(t) as functions?

Thank you in advance!

I have a problem for dsolve for equations.How can I remove it?

"too few boundary conditions: expected %1, got %2\"",20,19

thanks

FEW_BCS.mw
 

Download FEW_BCS.mw

GREETINGS

How to derive a maple code for this attachment.

Anybody know how to put this in coding for Jacobian Matrix? 

     Hi,

i want to solve equation system u0(x,t),u1(x,t),v1(x,t),v0(x,t)v2(x,t) dependent on f(x,t).

I attached file. 

Thanks in advance.

worksheet.mwworksheet.mw

Maple gives me a null output for an equation that has a real solution.

solve(4/x^(1/3)+1=0)

The following command seems to work

solve(4/surd(x,3)+1=0)

-64

Why doesn't this have a solution over the complex numbers, when real numbers are a subset of the complex numbers. Mathematica has the same result too.

Converting a VectorCalculus vector to a PhysicsVectors vector and reconverting it back
to VectorCalculus vector do not return the same result !
is this a bug ? Any clue ?

Download BugConversion.mw