MaplePrimes Questions

Hi, I am new to maple, and I am just trying to get to grips with it but I need to know how to do the following (I have been looking through the help guide but everything I try seems to not work)

1). I need to find the coefficient of xyz2 via a single function (Rather than just finding it once expanded or in a multistep process) to the equation (x+y+z)4

From what I have worked out its something like coeffs(expand((1)), x, y, z^2), but I am going wrong somewhere ...

let w=exp(2∏i/n) with i=√-1

find (1-w)(1-w^2).....(1-w^n-1) for n=3,4,5.

 

what do you think the general result might be for all n???

 

any help appreciated:)

Is there a way in Maple to compute a radical ideal?

 

For example, how to compute radical ideal of "a+b" with a,b in any field?

 

Thanks in advance.

Gepo

Tank you "Preben Alsholm". Your solution is very nice. But I have a question. When I use

implicitplot(eq(x), x=0..10)

for myself equation, I have a plot with 2 lines where have symmetry with respect to x-axis, but when I use your notation I only have the line under x-axis. Why?

For my physically work I need the upper line.

Hi!

I have one equation consists of "x" and "y(x)". This equation does not have any analytic solution, but I found a numeric solution by using "implisitplot". But, apparently this solution is not very good because if I want to plot anything which is related to either itself or its derivatives such as:

a(x) := y(x) + 1

or

b(x) := diff(y(x), x) + 1

I don't have any good result. What shall I do? Can you...

Hi!

Thanks a lot. you solved my first problem. Now I have a new problem. Consider I have an equation like:

w(z) = 1-(2/H(z))*diff(H(z),z)

I want to plot "w" with respect to "z", but since with latter solving I don't have any functional form for H(z) I can't. What's your suggestion for this?

Thank you!

Say I have an equation like

equation:= (r,theta) -> J(0,5*r)*sin(r)*theta

(where J is BesselJ)

and I want to integrate 'equation' over 'r=0..5' or any other limit. 

With, "Int(trial2(r, theta), r = 0 .. 5)" or even by using "int" instead of "Int", I'm not able to solve the integral. Even by using 'evalf' I get the same result back. 

If I get rid of the 'theta' term from 'equation', of course the integration ends up as a real...

I want to verify a solution satisfies a given differential equation,

deq := diff(y(x), x) = y(x)/(x*(ln(x)-ln(y(x))));

sol := x = y(x)*exp(C*y(x)+1);

Because the differential equation and the solution are complex,I tried many way,but failed.

How can I verify sol is just a general solution of deq?

Can you help me? Thanks a lot.

Dear guys!

I know that an analitical solution of an aquation of order "n" like this is impossible. But I give you a simple example. For the equation y(x)^2+y(x)+x=0, we have a solution like y(x)=(-1+-sqrt(1-4*x))/2. But here we have an equation of the form

y(x)^(-0.2)*[y(x)^2-(1+x)^3-(1+x)^4]=1. I'm sure it has a numerical solution. What do you think? 

This is what I'm trying to do:

> d := 40*Unit(m);                      

> a := .170*Unit(m/s^2);

> x := d+(1/2)*a*t^2;

> plot(x, t);

Error, (in plot) the units `m` and `m/s^2` have incompatible dimensions

 

Is there any way to tell Maple that my t is a variable of seconds?

First problem:

I have the following loop within some longer code. If I execute the worksheet, the loop gets stuck in the "print(within*loop)" section and never stops. 

Second problem:

If I don't restart the sheet, Equation 3 doesn't do the 'subs' command properly. Also, if I put the "with(Package)" commands in the beginning, Equation3  also fails to do the subs properly. 

 

Thanks!

Hi! I have an aquation and I want to solve it numerically. How can I do that?

The equation is:

H(z)^(2*n)*(H(z)^2-K1*(1+z)^3-K2*(1+z)^4)=1-K1-K2;

where K1 = 0.27, K2 = 5*10^(-5) and n = -0.1.

Thanks a lot!

 

 I want to solve this

Hi

The function of my problem is:

f(x) = piecewise(x < 0, 0, 0 <= x, exp(-1/x^2))

where a=0,x=0.5 and ξ=.25 i want to find reminder of f(x),R, and then plot R-n plot(n is degree of diff)

Hint:

I am a beginner in maple, these days I am learning maple user manual.

There is an example given by the manual:

___________________________________________

x:=872349

while x>0 do

irem(x,7)

x:=iquo(x,7)

end do

____________________________________________

I retype them in maple, but maple always returns "Error, illegal use of an object as a name"

I check my statements carefully, it is the same...

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