I did change of variables as below:

Download simplifyss.mw

But I amezed when I use simplify command deteriorate my eq.

Why?

UPDATE

Thanks for checking. I verify I get the error and made screen shots below

When I add the convert() command, the error goes away. Here is screen shot

I am using Maple 2017, student version, on windows 7, 64 bit, home edition.

Original post

This is using Maple 2017 on windows.

With the following input, Maple pdsolve gives an error

pde:=diff(u(x,t),t)=k*diff(u(x,t),x$2);
bc:=D[1](u)(0,t)=0,D[1](u)(L,t)=0:
assume(L>0):
ic:=u(x,0)=piecewise(0<x and x<=L/2,0,L/2<x and x<L,1):
sol:=pdsolve([pde,bc,ic],u(x,t)):

However, if I add one line to convert the piecewise function above to piecewise, then pdsolve no longer gives an error. So the following input works

restart;
pde:=diff(u(x,t),t)=k*diff(u(x,t),x$2);
bc:=D[1](u)(0,t)=0,D[1](u)(L,t)=0:
assume(L>0):
ic:=u(x,0)=piecewise(0<x and x<=L/2,0,L/2<x and x<L,1):
ic:=convert(ic,piecewise,x):
sol:=pdsolve([pde,bc,ic],u(x,t)):

Notice the extra line. Why does one have to convert piecewise to piecewise to make pdsolve accept the input?

sorry did not write down the error message and I am writing this from school library PC. But if you try the first case, you'll see the error.

Hi! I have the system of differential equations

restart; with(plots); with(DEtools);

a := 1;

deq1 := u(s)*(diff(varphi(s), s, s))+2*(diff(u(s), s))*(diff(varphi(s), s))+sin(varphi(s)) = 0;

deq2 := diff(u(s), s, s)-u(s)*(diff(varphi(s), s))^2-cos(varphi(s))+a*(u(s)-1) = 0;

sol := dsolve({deq1, deq2, u(0) = 1, varphi(0) = (1/4)*Pi, (D(u))(0) = 0, (D(varphi))(0) = 0}, {u(s), varphi(s)}, numeric)

which is perfectly solved, but I need to convert it to Cartesian coordinates and draw a plot, so what I tried is

x := u(s)*sin(varphi(s));

y := -u(s)*cos(varphi(s));

plot([x, y, s = 0 .. 20])

But I'm getting an error "Warning, expecting only range variable s in expressions [u(s)*sin(varphi(s)), -u(s)*cos(varphi(s))] to be plotted but found names [u, varphi]"

I don't know why is this happens if I have a solution. For example, I can get solution for 2 seconds:

sol(2)

[s = 2., u(s) = 2.33095721668252, diff(u(s), s) = 1.02513293353371, varphi(s) = .213677391510693, diff(varphi(s), s) = -.242430995691885]

I posted my question at here https://math.stackexchange.com/questions/2314488/how-can-i-find-maximum-and-minimum-modulus-of-a-complex-number.
With Mathematica, I got min is 22/5. This result is different from my solution by hand.

Repeat my problem. Let be the number z so that $|z+1| + 4|z-1| = 25$. Find the greastest and the least of the modulus of $z$. How can I find greastest and the least of modulus of z with Maple.

How can we find ricci tensor of a metric attaced in given file that involve two unknown functions phi(r) and nu(r).metric.mw

i have an optimization problem, i want to maximize an expression using assumption, what should i do?

Download optimize.mw

I have final project to make a media for learning mathematic using maple. But I'm so confused to make a net of cuboid, anybody can help me? please :D

Why I receive this error:

Download Dchange.mw

It is evident that by repeated applications of the double-angle and product trigonometric identities, one may transform any monomial of the form sin(x)^p * cos(y)^q, where p and q are positive integers, to a linear combination of only first powers of sines and cosines.

Example 1:  The monomial  4*sin(x)*cos(y)^2 is equivalent to

Example 2: The monomial 16*sin(x)^2*cos(y)^3 is equivalent to             

How does one write a Maple procedure to do that transformation in the general case of sin(x)^p * cos(y)^q?

Dear All,

Please, could anyone point me out how to draw the beautiful Apollonian Gasket using Maple?

Thank you.

Very kind wishes,

Wang Zhe

Hello!

I crwated a polyhedron from by grouping vertices to faces, and faces to a shell. My goal is to convert the obtained object into a polyhedron, which behaves similarly as e.g. Archimedean solids generated by Maple. Is it possible? Thank you in advance!

Bests,

Andrzej

hello. how can i solve this integral. thank you

I am building an algebra 1 course for my school, and was wanting to create simple randomly generating practice sets for graphing points / lines / etc.

However, the Sketch answer type doesn't allow for any variable input like the other questions do. Is there a work around? 

Presuming a randomly generated $x and $y, is there any way to check to see if a student has plotted the point ($x, $y)?

I have an update below

I am student, and bought Maple student version 2017 and went through verification and activation with no probems and been using Maple for number of days.

But few days ago, I disconnected my internet service provider, and so now I have no access to the internet from my home PC where I installed Maple (I am writing this from  library)

Now at home, when I start Maple, I get a message saying that my licence will expire in 10 or 9  days or so. I do not understand this messge. Why it comes up now and did not come up before when I had internet access? 

Does one need to be connected to the internet all the time to use Maple? What if one does not have internet access?

I did remove one monitor from my PC also. Do you think Maple detected change in PC (one less monitor) and now it thinks this is new PC? But this makes no sense.

How do I tell Maple I have activated my Maple if I do not have internet access?

Update

After installing Maple 2017.1, now each time I disconnect from the internet, I am not able to start Maple !  I get this error

When I connect to the internet and try again, Maple comes up OK and it works. (it does NOT ask me to activate). I have allready activated OK before. This message only comes up when I am not connected to the internet.

This tells me Maple is trying to connect to the internet each time for some reason to verify my installation? But when if I do not want to be connected to the internet and still use Maple?

I never installed beta Maple or anything like this before. What to do to make Maple start without being connected to the internet? I did not change my PC.

Hello Members,

I've to export some Maple lines to a LaTex file. I used the Maple command "Export as" and I saved the file like a .tex file. But when I open that file, it doesn't work because my LaTex doesn't recognise the package \usepackage{maplestd2e}.

How can I do? I put also my file in the post!

Thank you :)