A population has a mean of 75 and a standard deviation equal to 21. Find the mean and standard deviation of a sampling distribution of a sample means with a sample size of 49.  

I am using dsolve to integrate a system of equations, and I am using stop_cond to stop the integration when certain conditions are met.

The problem is, I want the integration to stop when condition 1 AND condition 2 are met, but when I use, for example

stop_cond=[y(t)-2,t-4]

it stops as soon as ONE of these conditions are met, not both. I want it to stop when y(t) is equal to 2 AFTER t=4, not before.

Any suggestions would be greatly appreciated!

Hi, i just want to write this equation im Maple,  how do i do it ?

thanks

Hi

I'm trying to find all solutions to a system of polynomial equations. I've tried using Isolate from the RootFinding package and for some choice of parameters this works well. However changing the parameters (i.e changing some of the coeffients of the polynomials), I get the error message.

Error, (in RootFinding:-Isolate) decreasing address previous=1e0f0020 new=10010020!

Any ideas on what this means?  possible ways around it? or other functions in maple that would give me all solutions?

Thanks, Steve.

View 127_phase coloring.mw on MapleNet or Download 127_phase coloring.mw
View file details

I am trying to color  3D plots according to phase using color=argument(x)/Pi/2

I get different results depending on the form I enter the expression x, as shown on the worksheet. Any suggestions to make this consistent?

I was testing if Maple can prove/show limit(a*(1-F(a)), a=infinity,left)=0, where F(.) is a general cumulative distribution function. Though, I doubt Maple has the ability.  However, I come across with some other questions during the exploration:

1. how is maple exactly doing to find limit:
Let's first try a normal distribution case:
 

with(Statistics):
U := RandomVariable(Normal(s,t))  :
limit(CDF(U,x),x=infinity,left)  assuming t>0,t<infinity ;

Is there an explanation on how each of the different paragraph styles work?

I was experimenting the other day and some selected paragraph styles don't allow you to type any text at all.  Couldn't find anything in the help pages, or I might have just been looking in the wrong area.

Hi to everybody.  I have to manipulate a system of partial differential equation,one by one.I have in particolar to derive a lot of time my differential equations(shallow water equations),and then to group, to substitute and at the and I need time derivative in function of spatial derivative.

I'm almost done. The problem is that now every time that  I execute a command it takes  a lot of time. The entire file takes some minuts to compile. It's so slow.

Hi all,

Suppose that you want to solve x'(t)=f(x,t)   x(t0)=x0

The theory show that:

x(t+h)=x(t)+1/2*h*(F1+F2) where F1=f(x,t) and F2=f(x+F1,t+h)

SO I made procedure:

Is there a switch/case statement in Maple?  So that instead of:

if (a = a1) then

   b1

elif (a = a2) then

   b2

elif (a = a3) then

  b3

end if

Something like:

switch (a) {

case: a1 {b1}

case: a2 {b2}

case: a3 {b3}

}

???

I'm potentially going to have a long list of elif's and might need  more efficient way of doing it.

How do I plot a 3d helicoid?  I can easily plot a helix, but cannot figure out how to fill the plane to the axis, to generate the helicoid?

Leslie

Hi all,

while studying this ODE

I now have 77 points and I am getting worried as it may suggest I know 77 points worth of maple.

However, all my points come from asking questions.

I wonder whether two types of pointing should be created: one for very grateful receivers such as I and one for all you wonderful givers - thank you - who are prepared to shed light on so many questions.

Just a thought.

Hi,

I have been trying to get a numerical solution to the following ode system for weeks. I am new to Maple, and I think my issues might be with the coding rather than the maths.

I get the error message:

Error, (in dsolve/numeric/checksing) ode system has a removable singularity at t=0. Initial data is restricted to {v(t) = 0., Phi(t) = 0.}

I know there is a singularity at t=0, so I tried setting the 'range' option to something just above 0, but it is still not working.