Maple Questions and Posts

These are Posts and Questions associated with the product, Maple

I plot a curve with "plot" command, how to export the figure to .emf format file?

Please advise as to the proper coding entries needed in the triple integration palette  to transform from the Cartesian placeholders x;y;z to spherical coordinates rho; theta; phi so that the triple integration palette can be used in spherical coordinmates. Dr. Lopez alreadyb has a standalone template which does this but I would like to set a palette option for spherical  calculations.

 

Thanx

This is one of these silly ones that crop up every-so-often (and yes, beta, gamma are just the relativistic v/c and energy):

gamma=1/sqrt(1-beta^2);
solve(%,beta);

comes up with ±I*sqrt(-gamma^2+1)/gamma.

While this is not wrong it is nothing I want to throw at any student trying hard enough as it is to keep his/her head above water. What I want is beta=sqrt(1-1/gamma^2) and I am having a devil of a time getting Maple to do this. even doing it "by hand" the I comes in the moment I take the sqrt. "assuming" does not help (and when I try ...assuming beta::positive, gamma > 1 I get an error claiming these to be inconsistent).

What gives?

Mac Dude

Hi. 

 

I have this expresssion:

 

int(sqrt(1+(diff(f(x), x))^2), x = 0 .. 17)

I know the result is:

30.75115129-1.376953493*10^(-8)*I

 

But it takes 13 minutes for maple to get to that solution, and i do not need the part with the I, complex number.

 

Is there any way to make maple evaluate this expression without computeing the complex number? A setting in generel, or some function to put the expression into?

 

Thanks in advance!

 

Emil Kristensen

I would like to tell Maple to evaluate all numbers in an expression using floating point numbers (of a desired precision). Short example:

evalf[30](x^(1/12));

prints

x^(1/12)

while I want it to print 

x^(0.0833333333333333333333333333333)

Note that the real expression may be arbitrarily complicated. I know that it is possible easily because I have already seen this somewhere, but I don't remember it. 

How can I write a general procedure which will take an integer n and create n nested loops:

add(...(add(f(x_1,...,x_n),i_1=0..k_1),...),i_n=0..k_n);

Thank you in advance.

Is it possible to find all the solutions of the equation

abs(tan(x)*tan(2*x)*tan(3*x))+abs(tan(x)+tan(2*x)) = tan(3*x)

which belong to the interval 0..Pi with Maple?

 

 

Hi, the title isn't great as I didn't know how to describe this really. I need to solve the following equation for b:

y = (1-exp(-x*b))/(1-exp(-50*b))

When I put a value for y in, this is fine and fsolve gives me a numeric real solution. However, even when using RealDomain, it does not give me a real solution if I leave y as it is, and instead gives a 'RootOf' solution, which I don't really understand. This is the same whether using solve or isolate:

b=-(1/50)RootOf(_Zx-50ln(-y+ye^(_Z)+1))

I have the values of x and y for multiple data points and can put them in an nx1 matrix. Is there a way to replace x and y with matrices (with real numbers in) and solve for each set of points for b (ie there would be n values of b)? Obviously I could go through and put in each value of x and y but this would take ages, so was just wondering if there's a quick way to do this.

I have tried by simply putting matrices instead of the letter but get the error:

Error, invalid input: exp expects its 1st argument, x, to be of type algebraic, but received Vector(50, {(1) = -50*b, (2) = -49*b,...

Thanks for your time

James

Hi, 

 

I wish to be able to calculate the roots of the function f(p) by using the roots of the function h(p) and applying the bisection method due to the fact that the roots of h(p) bracket the roots of f(p) as can be seen in the graph below. I have done this before for another example when h:=J0(p); and hence i could use The commands BesselJZeros(0,n)/BesselJZzeros(0,n+1) to find the roots. So my problem arises with the finding the roots of h(p) and how to insert them into my bisection loop(underlined below).

Any advice would amazing. Many thanks


restart;

Digits := 30:
with (plots):
with(RootFinding):

#Define given parameters

R:=1: #external radius of particles, cm

d:=10^(-3): #diffusivity cm^2 per second

alpha:= 1: #fractional void volume

c0:=10^(-6): #concentartion of soltion in void volume of solid initially, moles per liter

C0:=0: #concentration of main body of solution initially, moles per liter

k1:=0.5: #constant in adsorption isotherm (ka)

k2:=0.75: #constant in adsorption isotherm (kd)

k:=2.5: #equilbrium constant for adsorption kinetics

n0:=(k1/k2)*c0:#initial amount absrobed on solid, moles per liter

V:=0.1: #volume of external solution, liters

W:=0.1: #weight of absorbant, grams

rho:=2.0: #solid aparrant density, g/cc

delta:=(1/d)*((p+alpha*k2+k1)/(p+alpha*k2));

beta:=W*alpha*d/(rho*V);

   

1000*(p+1.25)/(p+.75)

 

0.500000000000000000000000000000e-3

 

 

 

 

 


f:=p->(BesselJ(0,R*sqrt(-delta*p))*k*p-(R*sqrt(-delta*p))*BesselJ(1,R*sqrt(-delta*p))*(d*p/R + 2*beta*k/(R^2)));

proc (p) options operator, arrow; BesselJ(0, R*sqrt(-delta*p))*k*p-R*sqrt(-delta*p)*BesselJ(1, R*sqrt(-delta*p))*(d*p/R+2*beta*k/R^2) end proc

(2)

h:=p->(BesselJ(0,R*sqrt(-delta*p)));
plot([f(p),h(p)],p=-0.3..0,axis=-5..5,legend=["f(p)","h(p)"]);


 




proc (p) options operator, arrow; BesselJ(0, R*sqrt(-delta*p)) end proc

 

 

 

(3)



points:=5:
rts:= Array(1..points):
for n from 1 by +1 to points do
pl:=evalf(#**first root of h**);
pu:=evalf(#**second root of h, i.e n+1 root**);
pe:= (pl+pu)/2;
while abs(f(pe))>10^(-6) do
pe:=(pu+pl)/2;
if f(pu)*f(pe) <0 then
pl:=pe;
elif f(pl)*f(pe)<0 then
pu:=pe;
end if;
od;
rts[n]:=pe;

od;
rts[n]:=p[n];

 

 

Download spherical_continue.mw


 

Download spherical_continue.mw

Hi,

 

I am trying to plot union of regions in Maple 15. Each region is formed by a set of inequalities. I can see from online such a feature is available in Maple 17.

The code is:

> with(plots);

> I1 := inequal({x < 1, y < 1}, x = 0 .. 2, y = 0 .. 2, optionsfeasible = [color = "Brown", thickness = 2]);

> I2 := inequal({y > 1, x < 1}, x = 0 .. 2, y = 0 .. 2, optionsfeasible = [color = "Yellow", thickness = 2]);

> display(I1);      ---> This is working 

>display(I2);      ---> This is also working

>display({I1,I2});  ---> Not working.

The above is also attached in the worksheet.

Is there any other way to plot the two region. I am new to Maple. Please suggest me the alternative in Maple 15.

 

Thanks!

 

Hello there,

i got a question regarding derivatives in Matlab.

 

I got a function for a example:

f:=f1(y)*f2(x)

 

from this function i need the partial derivatives with respect to x and y, i can easily get them with

diff(f,x)

diff(f,y)

 

now i want to compute the derivative of f with respect to time t, assuming that y and x both depend on t - how can i tell maple that y and x depend on t?

 

thanks

ben

I want to find the solution in a special form.
How can I do it?
Here is what I tried:

(Maple)

(Maple)


In the left hand side u_1 is not changed in  D(u_1).
I want to substitute and evalute (differentiate) it.

Thanks,  Sandor

 

 

 

 

assume input 0.567

how to get a list [5, 6, 7] or [5;6;7]?

(a) Design your own 3-stage explicit Runge-Kutta method with one-step error O(h4).

(b) Test your method by solving y= −y. Confirm that the global error in your numerical solution

is O(h3).

Write a Maple procedure that solves for y(1) in the initial value problem

                     y= f(y),     y(0) = 1,

 

 

using a numerical stencil based on the nth order Taylor series expansion of y. The procedure’s arguments should include an arbitrary function f, an integer n representing the accuracy of the Taylor series expansion, another integer N representing the number of steps between x = 0 and x = 1. Pick a test problem and compare your results with the output of dsolve/numeric.

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