Hello,

I need to prepare for a final exam for a introdutory computer science course in Maple.
My professor gives us mutliple choice questions, short answer questions and wiritng some codes.

what is the most efficient way to study for my final exam? or how should i study for an computer science exam. I am not really use to preparing for such a course. 

Are there any websites that i can practice multiple choice questions?

I would appreciate any advice.

Thank you very much.

Hi. I am having trouble with maples command "Cross product", i don't know why it doesn't work. Can anybody help me? This is a screenshot of the problem:

This question is 99% similiar to an previously posted question, but this one has a little twist(s).

http://www.mapleprimes.com/questions/200101-Solving-For-Coefficients-Of-Polynomial-Equations

Here is the sample problem. Let's say I have the following equations

e1:=(a+b+1)x^2 + (a+1)*x^4 = 0;

e2:=(a-b)*x+ (a^2 - 1)*x^3 = 0;

One can immediately tell the system is inconsistent because on x^3, we have a = -1,1 but on x and x^2 we have a = -1/2

This is precisely the problem I am facing, my e1 and e2 will eventually get bigger (bigger as in the order of the polynomial will increase) and I keep facing inconsistencies.

However if I could find a way to code it so that I can ask Maple to solve only up to a certain degree it would be great. This will eliminate any inconsistency

For example, using the system I have here, the system is consistent up to order 2 (it will always start from constants and up to a certain power). So I will ask Maple to solve the above system up to order 2.

Here is a pseudocode I have been working on.

For i = 1..2 //this might be increased, but it will of course be finite and probably won't go past 10.

For j = 0..N

//N is the degree of polynomial

f[i]:= coeff(e[i],x,j);

end

end

//the above generates the equations, below will solve it

solve( { f[i], i=1..?} ,{a,b})

Note that the pseudocode assumes e[i] are expressions and not equations set to 0 (which is what I have). Is there an "un"unapply on maple?

edit1: have to sleep  (late where I am! Will check for responses tomorrow) thank you

In a local coordivates frame {B}, an arc whith center "coc" ,radius "radius" and angle between “alpha1” and “alpha2” can be plotted in XY plane of {B}. The coord {B} is in a Ref frame {O}. The homogeneous transformation matrix is “H”. How can I plot this arc in coordinate {O}？

solve 30a+75b+110c+85d+255e+160f+15g+12h+120i=800000 over the positive integers

g:=Groebner:-Basis([a-2.0*b,b-2], plex);

Groebner:-Reduce(a, g, plex); 

Error, (in content/polynom) general case of floats not handled

How to solve this problem simply？

now the equation is

d2u/dt2-(2*d2u/x2)+d2u/dxdt=0    

initial condition: u(x,0)=1-(xsign(x)), abslute x<1,0 otherwise. Assume sign(x)=-1 for x<0, 1for x>0 

 Ut(x,0)=cos(pix), bslute x<1, 0 otherwise , he didnt give any B.Cs

so I would like to know the analytical and numerical sols, and plots for the wave at t=2,4

for Numerical:   delta x=0.1, delta t=0.025, range 0..4

Good day,

How can this be corrected ''Error, (in dsolve/numeric/bvp) initial Newton iteration is not converging'' see the worksheet here VT.mw

Hi all,
can you help in that please?
How can I use this small procedure (root_of_cheb) as a sub-procedure in  the next procedure (EvalInt) ?
is it possible?

restart:
root_of_cheb:=proc(n)
   local xk,b,k:
   xk:=(k,n)->cos((2*k-1)*Pi/(2*n));
   sort([seq(evalf(xk(k,n)),k=1..n)]):
end:

EvalInt:=proc(f,n)
   local xk:
   xk:=(k,n)->cos((2*k-1)*Pi/(2*n));
   evalf((Pi/n)*add(f(xk(i,n)),i=1..n)):
end:

Thank you

with(PDEtools);
Es := 0.117108e12;
Ef := 0.78125e11;
l := 0.150e-6;
s := 0.500000e-3;
f := 0.5898334197e-6;
o := 0.9e-5;
d := 0.10e-17;
cb := 0.1e7/(19.9);
R := 8.3144621;
T := 298;





PDE := diff(u(x, t), t)-(diff(u(x, t)+o^2*Es*cb*u(x, t)^2/(9*R*T), x, x)) = 0;
IBC := {u(1, t) = 1, u(x, 0) = 0, (D[1](u))(1, t) = l*f/(d*cb)};
S := pdsolve(PDE, IBC, numeric, time = t, range = 0 .. 1, timestep = 0.1e-4, spacestep = 0.1e-6);
p1 := S:-plot(t = .1, numpoints = 100);
Error, (in pdsolve/numeric/plot) unable to compute solution for t>HFloat(0.0):
matrix is singular
p2 := S:-plot(t = .2, numpoints = 50, color = green);
Error, (in pdsolve/numeric/plot) unable to compute solution for t>HFloat(0.0):
matrix is singular
p3 := S:-plot(t = .3, numpoints = 50, color = blue);
Error, (in pdsolve/numeric/plot) unable to compute solution for t>HFloat(0.0):
matrix is singular
plots[display]({p1, p2, p3});
Error, (in plots:-display) expecting plot structures but received: {p1, p2, p3}

I want to increase the stack limit. but i can not raise it above the hard limit....

so i wonder whether there is a way to increase the hard limit, or at least tell me how much is it?

I tried to use java to call maple command, but end up jvm crash. after some digging, i found the command i issued returned a rather huge string (around 40KB...).

Is this the reason why jvm crash? should i constrant the length of a command result when calling it from Java code?

Derive the orbit of the Moon around the Earth by doing a Verlet algorith of Molecular Dynamics simulation. Use one hour for your step τ. Place the stationary Earth at the origin of the Cartesian system. For initial conditions, use the position and the speed of the Moon when it is at its apogee (furthest from Earth). Plot the orbit.

(a) Show that if {an} ∞ n=1 is Cauchy then {a 2 n} ∞ n=1 is also Cauchy. (b) Give an example of a Cauchy sequence {a 2 n} ∞ n=1 such that {an} ∞ n=1 is not Cauchy

Hi, I'm trying to solve a system of equation and I keep getting this error. Could anyone help me figure out what I'm doing wrong?

My problem is:

> alpha := .3; G := 3.5; L := 6; f := 1.1;

for i to 50 do

I0 := x(z)+y[i](z); ICon := x(0) = 1, y[i](0) = 0;

for j to 50 do

i <> j;

d1 := diff(x(z), z) = -G*x(z)*y[i](z)/IC-alpha*x(z);

d2 := diff(y[i](z), z) = G*y[i](z)*y[j](z)/IC-alpha*y[i](z);

dsys := {d1, d2};

F := dsolve({ICon, op(dsys)}, [x(z), y[i](z)], numeric);

end do;

end do;
Error, (in dsolve/numeric/process_input) unknown y[2] present in ODE system is not a specified dependent variable or evaluatable procedure