## Real Numbers vs. Complex Numbers...

When I solve the equation like so;

fsolve(x^3-6x^2-7x+58=0) I get an answer in real numbers

and when I solve the equation like this;

solve(x^3-6x^2-7x+58=0) I get an answer in complex numbers.

How is it possible that when solving the same equation I get two different answers one with real numbers and the other with complex?

## Warning, solutions may have been lost...

eqn1:= 1.x+1.y+1.z=0

eqn2:= a.x + b.y + c.z=0

eqn3:= b.c.x+c.a.y+a.b.z=1

When I try to solve this system of equations as:

solve( {eq1,eqn2,eqn3},{x,y,z} )

I get the message "Warning, solutions may have been lost"

Can you please help me to solve these equations and express my solutions in "factored form" ?

## solving linearized poisson-boltzmann eq...

Dear all,

I would like to solve the following equation (linearized Poisson-Boltzmann in 2D) in Maple:

diff(u(x,y),x,x)+diff(u(x,y),y,y)-k^2*u(x,y)=0;

subject to the boundary condition:

u(x,a*cos(bx))=0 and  u(x,y)|y->infinity=0

(a,b and k are parameters)

I succeed to get the solution with pdsolve, my problem is how to solve the boundary condition problem.

Thanks!

## Ambiguous Naming...

Gurus...

Any idea why I get the "Parts of the expression are ambiguous. Please select one of the suggested meanings." alert on some of this code, but not other parts? I want them all to be "table assignments" not "function definitions" (per my options in the window). I would really like to not have it keep asking me the question on each run, so is there a way for me to be more specific? Thanks in advance!

Fred

deq(i,XMethanol):=M*diff(X[i](t),t)=(L*(X[i-1](t)-X[i](t))+V*(Y[i+1](t)-Y[i](t)));

deq(i,XWater):=XW[i](t)=1-X[i](t);

## Using Maple to rearrage equation into real and ima...

I have these 3 equations i am trying to rearrange into real and imaginarry parts. This is pretty easy execpt I am unable to rearrange C(k) into real and imaginary parts.

C(k)= H1(k)/ (H1(k) + iH0(k))

## Piecewise equations...

Is it possible to solve piecewise equations in maple? All I get is 'warning, solutions may have been lost'.

solve((piecewise(x<0,x,x>=0,x^2)=0));

Thanks.

## Hypergeometric function with small arguments...

I am trying to evaluate the hypergeometric function : hypergeom([1],[1.5],-z) where z is in the order of 1e-6. Its taking very long time where as if I use maple through matlab, then its quite fast !!. Evaluation of Gauss-hypergeometric functions for the similar arguments in maple is quite fast.  Is there any trick I can use for the fast computation of the confluent hypergeom in the case above?.

Thanks for any help

## RAM overflow when increasing DIGITS, while using L...

Good evening everyone

I am trying to solve this new problem the whole day up till now and as it is getting very late, I thought asking someone smarter than me might help in the end.

What I experience at the moment is that a written program of mine, as given below, works pretty well, when I set Digits to 10 or less. 100000 loops are not a problem. Yet, as soon as I start increasing Digits to values greater that about 15, my program crashes after about 100 loops. I can see what is happening: The RAM (2GB), is full.

## Convert to a Mayan Number...

I was wondering how you would convert a number to a Mayan number using Maple11.

## expand,combine,etc...

I have the expression

(r(r+(1/2)*s))(sin(t)/(r+(1/2)*s)+(diff(y(x), x))/(r^2+(1/2)*rs))

and I want to obtain

r*sin(t)+diff(y(x),x)

I tried expand,collect,combine without success.

Hopefully I missed something and there is a simple solution.

Sandor

## Another Dirac Plotting Query...

I have been reaading previous posts on plotting Dirac functions; in particular: Plotting the Dirac Function and How do I plot Cos(w*t) in frequency domain?

## Series with Maple...

I'm doing a series expansion of complicated expressions using Maple. How can I limit the number of terms, and not the order of the series? To be more precise, I need the series up to x^2, but when I ask for series(expr,x,3) I get terms of x^(2.5) which I don't need. How can I get rid of them without dropping the x^2 terms? series(expr,x,2) truncates them.

Thanks a lot to whomever can help!

## Export 3D Plots as DXF fails(?)...

Hello Maple experts,

## Plotting a procedure is this possible? tia sal2...

Plotting a procedure is this possible?

Greetings All

I’ve worked out a Fourier Series Expansion using excel and verified it by graphing it in excel to check my results.  See example

http://demos.onewithall.net/discrete_fourier_expansion_coefficients.jpg