I'm not sure why im getting a complex solution for evalf(h(-1/2)). Posted screenshot here:

http://prntscr.com/8abmta

The answer should be positive 6*2^(2/3) ≈ 9.52

 The computer returns

h(-1/2) =

=

The problem is that evalf((-1)^(1/3)) you get 0.500 + .866I

Is there no way to evaluate a second derivative of a real valued function which has a fractional exponent without receiving complex results? I don't have the time to look at each function and try to figure out what went wrong. I want to plug in any x value into a function defined for all reals and get a real result.

I tried  assume(x , 'real' ) , that did not do anything.

hi, I just want to calculate Adomian's polynomial but does not got  desire result,plz helpADMP.mw

hi .how i can solve nonlinear equation with unknown prameter omega as below

thanksfrekans.mw

Hi All,

I have o problem with simplify. A variable cp1r has been assumed to be positive. Why simplify still has csgn(cp1r) for it? Here is my code:

tmp := subs(cp1t(t)=cp1r, cp2t(t)=cp2r, Ca[2]);
1 / 2 2
----------- |-cp2r sin(x[1]) sin(x[7]) cp1r
2 2 |
cp1r cp2r |
\

2
+ 2 cp2r sin(x[1]) cos(x[1]) cos(x[7]) sin(x[7]) cp1r +

1 / 2 2 /
-------------- \cp2r cos(x[1]) cos(x[7]) sin(x[7]) \
(1/2)
/ 2\
2 \cp1r /
2 \\\
-2 cos(x[1]) cos(x[7]) sin(x[1]) + 2 sin(x[1]) cos(x[1])//|
|
|
/
assume(cp1r > 0, cp2r > 0);
simplify(tmp);
1 / / 3 3
---------- \sin(x[1]) sin(x[7]) \-cos(x[1]) cos(x[7])
2
cp1r cp1r

+ 2 cos(x[1]) cos(x[7]) cp1r csgn(cp1r) cp1r

2 3 \ \

- cp1r csgn(cp1r) cp1r + cos(x[1]) cos(x[7])/ csgn(cp1r)/

should csgn(cp1r) be simplified to 1 already? What is wrong with my script?

Thanks 

Everett

Maple does not cope with the following simple example:

with(geom3d):

point(A,0,0,0), point(B,1,0,0), point(C,2,0,0), point(E,2,1,0):

AreCoplanar(A,B,C,E);

           Error, (in geom3d:-plane) the points may not be AreCollinear

Should we interpret this behavior as a bug? I think I met with this yet 10-12 years ago, but unfortunately since then nothing has changed.

I have the following PDE:

u_xx = u_tt + (2^{1/2}u_x-u)^{1/2}

Do you have a proposed algorithm to solve in maple for this PDE? I mean pdsolve won't solve it because it's a nonlinear PDE.

Hi All,

I am working on modeling dynamics for a robot. It requires a write some long expressions into C++.  When I do it, it has some strange problem in creation of C++ code from a vector.

Here is an example of the problem. I have a multivariable polynomial term, I using coeffs to get its coefficients and corresponding unevaluated variables, which works fine. But I can't convert the vector into C++

Ca := coeffs(term, [W, Rf, Rr, dxf, rcf, rcr], 'L'):

L;                           Rf, Rr, dxf

C(L, resultname="L11", output="dSpDdx1.cpp");

Error, (in Translate) options [Rr, dxf] not recognized.

I don't know why maple thought the unevaluated variable Rr and dxf are options instead of the vector I want to convert into c++. Does any one know what I did wrong?

Thanks in advance.

Everett

Just purchased Maple 2015 and playing with it for the first time.  I'm running the 64-bit version on Win 8.1.

Anytime the program generates a pop-up dialog box, the pop-up seems to get stuck behind the main program window.  I can't alt+tab to get to the pop-up window and I can't click on anything in the main program window because it's frozen while waiting for me to aknowledge the pop-up dialog box.  So I have to kill everything from the task manager and lose anything that's unsaved.

I'm talking about pop-ups for things like "Error, (in @@) invalid arguments"... I click on the link and see a brief flash while that pop-up quickly flies behind the main window.  Same thing happens when I click on a link that asks what web browser I want to use.

I can't be the only one that has this problem, so is there a fix or workaround for this somewhere?  It's not really useable like this.  Thanks!

k^4-k^2*(4*u*m+2*q^2)+k*(8*m*E*q)+4*m^2*(D^2-e^2+(q^2/2*m-u)^2)=0

This is my first attempt at trying the units feature within Maple. I have had mixed results. I have a function defined that gives me values in [cal/mol/K], which is correct. But when I try to use this as the integrand in an integral definition it does not want to solve. I cannot determine what the problem is.

I thought that I possibly needed to define units in the integral expression, but this just produces more errors or locks-up Maple completely. (Side note: When Maple locks-up, the "interupt current operation" toolbar often does not correctly kill the operation, and I am forced to restart Maple :/)

As I have the problem defined, I should get the following result:

T__sys= 64.47487 [K], should get me HIG(T__sys) = -19682.7 [cal/mol].

See attached: EnthalpyTrace_-_Integrating_with_Units_Error.mw

Any help or insights would be greatly appreciated.

LE_EQ.mwWhat is problem with this programme,why it does'nt calculate the values but only shows the solution with integral sign instead of calculating it, there is also arising a problem in plots

dsolve thousands of system with for loop

but one of system run a very long time, seems never end, just stuck here

how to set timeout when impossible to dsolve

ics:=a(1)=0,b(1)=0,c(1)=0:
ode:=rhs(a4[ii])[1]=1,rhs(a4[ii])[2]=1,rhs(a4[ii])[3]=1:
ode:=a(t)*c(t)*(diff(c(t), t))+2*a(t)*(diff(a(t), t))*b(t) = 1, a(t)*(diff(a(t), t))*b(t)*(diff(b(t), t))*c(t)*(diff(c(t), t))+a(t)*(diff(a(t), t))*b(t)*(diff(b(t), t))+a(t)*(diff(a(t), t)) = 1, a(t)*(diff(a(t), t))*c(t)+2*a(t)*b(t)*(diff(b(t), t)) = 1;
dsol := dsolve({ode,ics}):

Does Maple TA work in Windows 10?

My first attempt in Edge and Chrome was not promising.

Harry Garst

hello guys,

i have 4 differential equations with 4 unknown functions and i want to find functions , what is your idea ?

diff.mw

thank you very much