pick_pos.mw

Hey maple gurus

when i solve and equation with two real roots (1 positive and 1 negative roots), how do i automatically pick out the postive solution?

As you can see from the attached file, i used sort command to order it, and it works for examples1 and 2, but not for 3.

i guess i could use Abs cmd.....

I want to find the first term and the common difference of the arithmetic progression (un) with the following condintions u7 + u15 = 60 and (u4)^2 + (u12)^2 = 1170, but i can not the code. Please help me. Thank you.

given differntial equations with boundary conditions.

f'''(x)+f(x)f''(x)+1-[f'(x)]^2+A*{1-f'(x)-(x/2)*f''(x)}=0,
g''(x)+P*[f(x)*g'(x)-f'(x)*g(x)-A*{g(x)+(x/2)*g'(x)}]=0,

bc's

f(0)=k,  f'(0)=m, g(0)=1, 
f'(infinity)=1, g(infinity)=0

Dual solution exist in the given problem with shoot command i think. how we ll calculate them?

NOTE:

This thread stimulated me into playing with a few ideas,

I pieced together this little newton-raphson procedure...

> newton := proc( f, # the function x0 # the initial guess n, # step count limit tol # error tolerance)

local x, g, k;

g := D(f); # the derivative f’(x)

x[0] := evalf(x0); # initialize the iteration

for k from 1 to n do # loop for newton’s iteration

# Newton’s iteration formula

I can not get any subscription in the forum for any topic. Activating the subscription link directs me to the page:

http://www.mapleprimes.com/controls/#


Without the subscription validity.

The goal is to find generating function of Hermit

Before i try, i try the gFun's paper's example, got error

with(gfun):
eq := {z^2*diff(y(z),z)+y(z)=z, (D(y))(0)=1};
eq2:=borel(eq,y(z),Y,'diffeq');
Error, (in gfun:-borel) invalid argument, Y

When try Hermit,

with(gfun):
eq := {t*diff(y(z),z$2)-z*diff(y(z),z)+y(z)=0,y(0)=1,y(-z)=y(z)};
dsolve(eq);

but have unknown constant coefficient, do not know whether missing initial condition

I am trying to solve the system of equation by maple but its not giving the correct answer.

> e1 := (1/2)*alpha*alpha[3]^2*q[2]^3-V*alpha[4]*q[2]^2-V*alpha[0]+(1/2)*alpha*alpha[0]^2+(1/2)*alpha*alpha[1]^2*q[2]+(1/2)*alpha*alpha[2]^2*q[2]^2+(1/2)*alpha*alpha[4]^2*q[2]^4-V*alpha[2]*q[2]+C+alpha*alpha[3]*q[2]^2*alpha[1]+alpha*alpha[4]*q[2]^3*alpha[2]+alpha*alpha[4]*q[2]^2*alpha[0]+alpha*alpha[2]*q[2]*alpha[0];
> e2 := -gamma*alpha[2]*q[3]*q[2]^2+2*beta*alpha[4...

I was using "eliminate" to combine a set of equations removing some variables and getting a clearly wrong result. So I looked at the docs and the first example, and I find I don't understand its result either. Here is the example:

sol:=eliminate( {x^2+y^2-1=0, x^3-y^2*x+x*y-3=0}, x); # eliminate x from this set & leave one eqn of y

This returns:

Hi

I am trying to fit some data to a model.

The model is given by this equation.
y=a*(1-exp(b*x^c))

When I enter the command

Statistics[Fit](a*(1-exp(b*x^c)),X,Y,x);

this error message appears:

Error, (in Statistics:-Fit) SVD of estimated Jacobian could not be computed

 Does anyone know, why it appears? and why Maple cannot compute the SVD of the estimated Jabobian Matrix? 

Please help me with the next problem in Maple. When I try to find roots using solve command but

it throws the next message:

Warning, solutions may have been lost...

The procedure is performed as follows:

fx := (-(1/2)*(sqrt((x-x1)^2+(y-y1)^2)-m1)^2*(2*x-2*x1))*(1/(s1*sqrt((x-x1)^2+

(y-y1)^2)))+(-(1/2)*(sqrt((x-x2)^2+(y-y2)^2)-m2)^2*(2*x-2*x2))*

(1/(s2*sqrt((x-x2)^2+(y-y2)^2)))+(-(1/2)*(sqrt((x-x3)^2+(y-y3)^2)-m3)^2*...

Hi,

I have a table T where the indicies are pairs (a,b) of integers with 0<a,b<50. Is it possible to make a 3D plot with a point (a,b,T(a,b)) for each (a,b) in the domain of T?

Hi,

eq1:=diff(f(eta),eta,eta,eta)+f(eta)*diff(f(eta),eta,eta)+beta*(1-diff(f(eta),eta)^2)=0;

eq2:=diff(theta(eta),eta,eta)+pr*f(eta)*diff(theta(eta),eta)+pr*Ec*(diff(f(eta),eta,eta))^2+(2-beta)*pr*Q*theta(eta)=0;

bc:=f(0)=gama,D(f)(0)=lamda,D(f)(N)=1,theta(N)=0,D(theta)(0)=-Nc*(1-theta(0)):

gama:=-1.5:Ec:=0.5:
lamda:=1:
Nc:=3:
pr:=5:
beta:=1:
 N:=5:for Q from -1.5 to 1.5 by 0.1 do A[Q]:=dsolve({eq1,eq2,bc},numeric, 

How can I archive color coding? The two plots are colored the same, but I want them to be colored according to one common color scale, which means that each z value is assigned to a unique color for the 2 function plot.

f1 := proc (x, y) options operator, arrow; sin((1/2)*y+(1/2)*x) end proc;f2 := f1+2;
p1:=plot3d(f1, 0..10, 0..20, style=patch, color=proc(x,y) x*y end proc);p2:=plot3d(f2, 0..10, 0..20, style=patch, color=proc(x,y) x*y end proc);
plots[display](p1,p2);

Hi

I have .dat files that I want to use in integrating some function, say

f(x)=int(1/a(x),x),

where I have the numerical values of a(x) as "avalues.dat" file.

I am wondering if there is a command that does the integration numerically...

And also for  differentiating numerically: g(x)=diff(a(x),x)

Thanks in advance.

In geom3d, how can i make a triangle which coordinates of the center circle circumscribed triangle are integer numbers? Please help me. Thank you.