Suppose I want to revolve the curve given in the (X,Y)-plane by the set of parametric equations

x(t) = cos(t) + t sin(t)

y(t) = sin(t) - t cos(t)

for t in [0,Pi/2] around the X-axis. How can I plot the given surface of revolution? Similarly, the same question for

x(t) = exp(t)*cos(t)

y(t) = exp(t)*sin(t)

for t in [0,Pi/2]

giratore.msim which error?I can't see V and I?thanks

How to plot an Elliptical Function of Third kind complete or incomplete, eg. EllipticPi(n,k) if n and k are not constants?

as The function I wish to plot and explore contains Elliptical Function of Third kind complete and incomplete with complicated form of n and k.

Please reply asap.

Regards

Hi everybody,

I have differential equation of the form eq := diff(x(t), t) = x(t) + 1  and I want to find the name of the dependent variable (more generally this issue concerns a differential system in N dependent variables).

How should I use “indets” in order to obtain {t, x(t)} ?

(indets(eq, name) returns {t}, while indets(eq, function) returns {t, x(t), d/dt x(t)}.

Thanks in advance

Perhaps I am being stupid, but I have a problem with functional operators, more specifically with looping through a collection of them. Consider the following code (just a study case):

nonIdMaps := []:
for f in [x -> x,x -> 2*x,x -> 3*x] do
   f,f(y);
   if f(y) <> y then nonIdMaps := [nonIdMaps[],f] end if
end do;
nonIdMaps,map(f -> f(y),nonIdMaps);

There are two things I do not understand about this output: 1.) Why the f's rather than the specific maps as given in the list? 2.) Why two times 3*y in the last line, rather than [2*y,3*y]? (this issue being of course quite likely a consequence of the first one). This behaviour can be compared with the following:

nonIdMaps := select(f -> f(y) <> y,[x -> x,x -> 2*x,x -> 3*x]):
nonIdMaps,map(f -> f(y),nonIdMaps);

the output of which I do understand, being as I expected it to be. I guess that there are some scoping rules I do not understand, or what?

how would you interpret the solutions to this:

>int(sin(y/2)^2/(x*(x-y)*y^2), x=omega__ir*t..omega__c*t) assuming t::positive, omega__ir::positive, omega__c::positive, omega__c>omega__ir;
 

which leads to the expression shown in the screen shot. In particular, I'm interested in the condition for the solution to be "undefined"

thanks.

If I make a single plot it will always be located in the centre of the worksheet. Is there an option to place it at the left border?

Dear friends,

I have to solve the BVP of the following type:

(x-1)*y''(x)+y'(x)=1+x, y(0)=1, y(1)=1

Expressing the highest derivative (y''(x)), we get a singularity at x=1.

So, as recommended, the method bvp[middefer] (or bvp[midrich]) is used:

dsolve({(x-1)*diff(y(x), x$2)+diff(y(x),x) = 1+x, y(0)=0, y(1)=1}, type = numeric, method = bvp[middefer], y(x), 'output' = Array([seq(k/10, k=0..10)]), 'abserr'=1.0e-3, 'maxmesh'=100)

Maple generates the following error:

Error, (in dsolve/numeric/bvp) unable to achieve requested accuracy of 0.10e-2 with maximum 100 point mesh (was able to get 0.82e3), consider increasing `maxmesh` or using larger `abserr`
But as I increase maxmesh, the achievable accuracy (reported in "(was able to get XXX)") decreases:

for

maxmesh = 200: 0.19e4

maxmesh = 500: 0.54e4

maxmesh = 1000: 0.12e5

maxmesh = 5000: 0.73e5

and so on.....

How to solve this equation with desirable accurancy and usage of Array as output?

i want to solve an ode , but maple return an integral in result, how can i have an answer?

Download dsolve.mw

 Dear Maple users,

In Maple 18, I want to  label y axis as $\hat{\sigma}_y$.

labels = [x, sigma[y]] works fine but I have no idea how to put a hat on sigma[y] .

regards,

Using Tools -> Check for Updates, I have just tried to update my Maple installation from 2017.0 to 2017.1. The download itself went without a hitch, but then nothing happened. In view of the fact that I clicked a button titled 'Download and Install', I would certainly expect the installation to have started automatically after download. Are anyone else experiencing the same odd behaviour?

PS: Related question of mine is Automatic update of help pages?

Limit of function f(x)=[arcsin(x)]/tan(πx/2).  At point x=1

I can't take the inverse laplace transform of one kind of functions.

Would you like to help me?

Thanks.

hello,

i went to plot a complex numerical solution , i used odeplot but did not work

please help

Thank you very much 

Download mapleprime.mwmapleprime.mw

I created a loop to calculate, using random numbers, the probability of a die roll. I got 0, which I originally attributed to the fact that the probability might have just been that low, but in comparing it to a binomial distribution, it shouldn't be 0.

I tried editing the loop to do a coin toss instead, where the probability is 0.5, and that worked fine. So I don't think my loop structure is necessarily wrong. But perhaps I wrongly input getting a 0.167 probability somehow.

Any advice would be appreciated!

dierollfail.mw