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Im having trouble with the DEplot command, i seem never to be able to use the plot commands on maple no matter what i do. Heres what i've got so far. > eq1 := diff(n(t), t)+lambda*n(t) = 0; / d \ |--- n(t)| + lambda n(t) = 0 \ dt / > eq2 := dsolve([subs(lambda = .1, eq1), n(0) = 10]); / 1 \ n(t) = 10 exp|- -- t| \ 10 / > with(DEtools);

In the help, it writes

BesselJ and BesselY are the Bessel functions of the first and second kinds, respectively. They satisfy Bessel's equation:
     2                2    2
    x  y'' + x y' + (x  - v ) y = 0

My problem is in statistics. I'm looking for the resulting normalized distribution funtion.

Given a sample has a normal distribution of trait A, and given a subgroup that posseses trait B with a different normal distribution of trait A. Waht would the distribution of trait A be if we eliminate the subgroup that posseses trait B.

The following example that assumes a subgroup of 20% does not yield the proper result.

f := x -> if(x<=0, 0, 1):

Why do the first two plots work, but the third and fourth doesn't? How do I plot the sum of this function in a specific range?

How do I get a closed-form expression?

I tried the following (e.g.):


> k[21] := t-> piecewise(t<0,0,p*(1-p)^t);                      {definition of descrete probability distribution, here: geometric distribution}

I want  to calculate the derivative of Bessel, I do

In 13.01 (Linux) I see this.

> # works ok
> plots:-spacecurve([sin(t),t,1],t=0..1,thickness=5);

> # expect missing argument error, but loses kernel connection
> plots:-spacecurve([sin(t),t,1],thickness=5);

Is it the same in 13.02, and on Windows, can anyone say?

Dear Maple Experts,

  I'm fairly new to Maple.  I've been trying to compute Gaussian tail probabilities accurately.  As I understand it, Maple has an "erf" function, but not an inverse erf.  Other posts have suggested doing something like:

  inv_erf := x->solve(erf(y/sqrt(2.0))=x,y);

At first ; for instance, about 68% of a Gaussian's probability is within 1 standard deviation, so:

> erf(1/sqrt(2))


> evalf(inv_erf(0.6826894920));

Hi everyone, I have question that i cannot solve.

The question is : 

Write a procedure named MULTIPLYMATRIX to find the product of an n x m matrix by an
m x q matrix. Your procedure should print the result matrix. The dimensions n, m, q should be
input parameters in your procedure. Test your procedure by demonstrating multiplication of a 2 x
3 with a 3 x 4 matrix of your choice.


I mean when typing polynomials, convert the 2x4 to 2x^4,,,

for 4 is in the right

and sometimes I'm a little lazy(?).



a is "coeffs(p1)"

b is "coeffs(coeffs(p1, {x, y}))"

c is "coeffs(p1, [x, y])"

d is "coeffs(p1, x)"

e is "coeffs(p1, x, y)"

the results of a,b,c are the same

8, -6, 12, 4, 1, -4

and the results of d,e are the same

4*y^2+12*y+8, -4*y-6, 1

question 2:

I'd like to get the both resuls of "coeffs(p1, x)" and "coeffs(p1, x)" at the same time,

what's the simplest way?


I have some calculations/results which I use in many other documents. Is there anyway to link to this document that contains results I need for another sheet in the beginning of the sheet I need the calculations for?


Thanks in advance

Regards Brian

If you make a misspelling in spacecurve as in

plots:-spacecurve([ARctan(t),t,t], t=0..10);

then Maple 13.02 (Standard) loses contact with the kernel.

Even if you forget 't ='  as in


Maple will lose contact.

It seems that also Maple 12 has a problem.

Maple 13 Classic doesn't have the problem.

Will these and other 3d-plot problems be corrected in Maple 14?


Preben Alsholm

How do I write a loop to store a set of values for t and n(t) into an array?


I wrote a loop to get the values:

>for t  from 1 by 1 to 25  do print(t, f(t)) end do


but don't even know where to begin with putting them into an array.

Thanks for any help.

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