## How can I solve a set of equations that one of the...

Asked by:

I solve a set of equations in this way and I have three set of answers ,but I don`t know wich one is true.

and I have another question ,how can I assume v[0] like a constant?

alpha[2]:= 2.727272728*10^5: alpha[4]:= 3738.685337: alpha[6]:= -30.18675539: alpha[7] := -4.116375735*10^6: alpha[8] := 1.859504132*10^10: alpha[9]:= 2.489142857*10^(-12):

l10:=(alpha[7]*v[0]^2+1)*gamma[i*n]^4+(-alpha[4]*beta[n]^2+alpha[8]*v[0]^2-alpha[9])*gamma[i*n]^2+(2*I)*gamma[i*n]*alpha[2]*beta[n]*v[0]+(2*I)*gamma[i*n]^3*alpha[6]*beta[n]*v[0]-beta[n]^2 = 0:

l11 := subs(i = 1, l10);

l12 := subs(i = 2, l10);

l13 := subs(i = 3, l10);

l14 := subs(i = 4, l10);

l15 := (exp(I*(gamma[n]+gamma[2*n]))+exp(I*(gamma[3*n]+gamma[4*n])))*(gamma[3*n]^2-gamma[4*n]^2)*(gamma[n]^2-gamma[2*n]^2)+(exp(I*(gamma[n]+gamma[4*n]))+exp(I*(gamma[2*n]+gamma[3*n])))*(gamma[2*n]^2-gamma[3*n]^2)*(gamma[n]^2-gamma[4*n]^2)+(exp(I*(gamma[2*n]+gamma[4*n]))+exp(I*(gamma[n]+gamma[3*n])))*(gamma[2*n]^2-gamma[4*n]^2)*(-gamma[n]^2+gamma[3*n]^2) = 0;

l1 := combine(expand(evalc(l15)), trig):

l2 := combine(expand(evalc(Re(l15))), trig):

l3 := combine(expand(evalc(Im(l15))), trig): v[0] := 1; 1

fsolve({l1, l11, l12, l13, l14}, {beta[n], gamma[n], gamma[2*n], gamma[3*n], gamma[4*n]}):

fsolve({l11, l12, l13, l14, l2}):

solve({l11, l12, l13, l14, l3}):

thanks

Reyhaneh

## Set of complexes ...

Asked by:

hi all

i have a set of complex numerics, so:

1- i want the numeric with least valence(potency) in imagin particle,

2- i want print the real particle of this numeric.

for example:

A:= .5464691235-.4473247264*I, -.4563184747+1.*10^(-14)*I, .5464691235+.4473247264*I

i want print: -.4563184747

plz help

## How to trim small imaginary parts?...

Asked by:

I know this has been dealt with before here, but I have forgotten the proper way to trim a small imaginary round-off from a result. I cannot locate the proper answer in MaplePrimes; and the Mapledocs are either quiet about it or it is hidden in a difficult-to-find place.

What I want is to ignore ny imaginary part below a certain threshold. Ideally, it takes the threshold in relation to the real part but I am not particular about this.

Thanks in advance,

Mac Dude

## Convert an equation with ln...

Asked by:

Im working on a assignment on maple. I have an equation of motion that looks like this:  v(t):= -g*t-vs*ln(r*t-m)+vs*ln(-m)
Im supposed to use this equation and solve it for t an later integrate it. Since the constant inside the ln is negative I end up with a annoying imaginary part. Is there any way to covert this equation so that the ln disappear, so that I can get a result whitout a imaginary part?

## Is Maple not good at imaginary domain ? ...

Asked by:

Hi , everyone who love Maple and dsolve command,

my ODE is :

sys_ode := diff(d11(m), m) = -(3*sin(m)^2-1)*d31(m)/a^(3/2)+(-3*cos(m)*sin(m)/a^(3/2))*d41(m), diff(d21(m), m) = (-3*cos(m)*sin(m)/a^(3/2))*d31(m)-(3*cos(m)^2-1)*d41(m)/a^(3/2), diff(d31(m), m) = -a^(3/2)*d11(m), diff(d41(m), m) = -a^(3/2)*d21(m)

using " dsolve([sys_ode]) " command could get the solution easily, and the solution contains "I" (imaginary domain).

However, when we substitute the solution into the ODE "sys_ode", find not correct !

we use the following command to check the solution :

simplify(  -diff(d11(m), m) -(3*sin(m)^2-1)*d31(m)/a^(3/2)+(-3*cos(m)*sin(m)/a^(3/2))*d41(m)  )

the upper expression is supposed to be zero, but not ! Is it a bug in Maple dsolve ?

## output of dsolve for given eq urgently required...

Asked by:

hello,

I'm trying to solve the equation of a form like,

diff(eta(tau), tau, tau)+(8/(4*tau^2+1)-32/(4*tau^2+1)^2)*eta(tau) = 0,

when I'm doing solve DE, I get a solution as:=

eta(tau) = _C1*sqrt(4*tau^2+1)*LegendreP((1/2*I)*sqrt(7)-1/2, I*sqrt(7), (2*I)*tau)+_C2*sqrt(4*tau^2+1)*LegendreQ((1/2*I)*sqrt(7)-1/2, I*sqrt(7), (2*I)*tau

which is combination of Legendre Polynomials with imaginary arguments,May I change this form,

How can I plot this solution on real plane, as this is imaginary,

Is the only option remaining NUMERIC PLOT??

## Non-fatal error while reading data from kernel...

Asked by:

I am trying to solve two differential equations numericaly:

## Get the imaginary and real part of a complex expre...

Asked by:

I am trying to get the real and imaginary part of a complex expression but it appears that the evalc(Im(F)) does not work. My guess is that i have to manipulate the expression before i use the evalc, but the simplify command for example did not give a result either. My funstion is F:=1+2*zs*I-w^2/ws^2-w^2/ws^2*ks*(1+2*zs*I)*(K3*(1+2*z3*I)-H*K2(1+2*z2*I)+H*(H*K1*(1+2*z1*I)-K2*(1+2*z2*I)))/(K1*(1+2*z1*I)*K3*(1+2*z3*I)-K2^2*(1+2*z2*I)^2);

As you see I have imaginary I...

by: Maple

## threshold for ignoring nonreal part in plots...

Asked by:

On the usenet newsgroup sci.math.symbolic Prof. Richard Fateman posted a question (or here) recently about what mechanisms a math application could use to handle the situation of negligible imaginary parts of computed data when plotting.

An example could...

## Using J Rather Than I for Imaginary Numbers...

Asked by:

Hello All,

How may I have Maple accept and output J, rather than I, for imaginary numbers?

Thanks,

Dave

## Drawing the contour of integration...

Asked by:

My contour of integration is a semi circle whose diameter rests on the imaginary axis from -ri to ri.  The arc of radius r is on the positive real axis going from -ri to ri.  On the curve I want to have directional arrows indicating that I am traversing this contour in the positive direction.  How do I create this figure in MAPLE?

## why does evalc give csgn?...

Asked by:

Hi,

I am trying to simplify the expression s as given below. (I am not sure why it comes up with all the vector caclulus notation in it but it should display okay when you enter it)

Because of the presence of the exponential imaginary fucntions I thought evalc might be useful but when I use it I get a huge expression with csgn appearing in it. To my knowledge csgn appears when assumptions are not correctly specified - is this so? I can't see any assumption...

## unwilling imaginary part...

Asked by:

Hi,

I'm trying to model a magnetic field with maple.

In order to do that, I compute a (huge) sum and integrals of real and posive numbers.

The problem is that for some points, when I compute the norm of this field I get an imaginary number with a very small imaginary part (egs -2, 27293.1844462+1.42305652280*10^(-84)*I ).

How can I get rid of it?

thx in advance

## Ho to isolate the real part of the equation...

Asked by:

Dear Sir / Madam,

Would you recommend me how to isolate the real and imaginary part and simplify the equation A? Maple cannot evaluate this equation to numeric value...

A := evalf(sqrt((Re(B))^2 + (Im(B))^2));
A := evalf(abs(B));

are not working.

I have attached my equation function.txt

 1 2 Page 1 of 2
﻿