Adri van der Meer

Adri vanderMeer

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19 years, 99 days
University of Twente (retired)
Enschede, Netherlands

My "website" consists of a Maple Manual in Dutch

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These are answers submitted by Adri van der Meer

I suppose that (1) and (2) are intended to be labelnumbers of equations. Enter these via Ctrl-L:



I understand that you read Dutch. So see , choose Module 7, for a complete explanation.

I will not do your homework, but here is a hint: f is a polynomial with 5 unknown parameters. So you have to solve 5 equations with 5 unknowns.

If you replace



z :=  x -> H/mg*(cosh(mg/H*x+zeta)-cosh(zeta));

the shifted plot wil be:

plot(z(x+deltax), x=0..1 );


Why should you use a procedure if you don't want to use a parameter sequence? But if so, you can refer to parameters outside the procedure via the -: operator. A simple example:


p,q := x^2+2*x+1, x^2-3*x+5:

f := proc()
  solve(:-p + :-q = 0,{x})
end proc:


{x = 1/4+((1/4)*I)*47^(1/2)}, {x = 1/4-((1/4)*I)*47^(1/2)}




The assignment x := LinearSolve(A, b) makes x a Vector (with parameter _t2), so it cannot be used as a range parameter. Replace it by v := LinearSolve(A, b), and don't forget to restart.

R2 is an 1x1-matrix, as to expect:

Matrix(1, 1, {(1, 1) = 44}, datatype = anything, storage = rectangular, order = Fortran_order, shape = [])


Make an operator that for multiplies the identity function with the derivative:


xD := f ->(x->x)*D(f);

proc (f) options operator, arrow; (proc (x) options operator, arrow; x end proc)*D(f) end proc








Because x and y are constants, there is no reason to try to calculate the sum symbolically.

add(binomial(y, i)*(1/3)^i*(2/3)^(y-i)*(add(binomial(x, j)*(1/3)^j*(2/3)^(x-j), j = i+1 .. x)), i = 0 .. y);

Make the colorbar as a separate 3D-plot, viewed from above (P2 in the worksheet)

restart; with(plots):
X2 := <seq(i,i=1..25)>:
X3 := <seq(2*i,i=1..25)>:
zz := <seq(-i^2+23*i+53,i=1..25)>:
M,m := max(zz),min(zz):
P1 := pointplot3d(X2, X3, zz, symbol=solidcircle, symbolsize=20, shading=zhue, orientation=[75,60,0]):
P2 := plot3d( y, x=0..20, y=m..M, style=patchnogrid, shading=zhue,orientation=[-90,0,0],tickmarks=[0,default,0], labels=["","zz",""],scaling=constrained ):
display( Array([P1,P2]) );



If you don't want to plot (a) solution curve(s), use dfieldplot:

dfieldplot(DE3, [y(x), z(x)], x = 0 .. 3, y = 0 .. 2, z = -4 .. 4, arrows = medium, dirgrid=[20,20]);

If you use a loop to place (some) answers in a set, it is more efficient to use a sequence as intermediate:


S := NULL: #empty sequence

for i to 5 do S := S,i end do:

S1 := {S}; #makes a set from the sequence S

{1, 2, 3, 4, 5}




To interchange the horizontal and the vertical axis, make F13 a parametrisized plot:

F13 := plot([-0.2e-1*sin(6*Pi*y),y, y = 0.25e-1*L .. .475*L], scaling = constrained):

The x=X substitution is not necessary:

Diameters := unapply(subs(Data, piecewise(x<L/2, d0 ,x<2/3*L, 2*d0 ,x>2/3*L, 1.5*d0)),x);
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