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))

    0.6826894920

> evalf(inv_erf(0.6826894920));

    0.9999999994

So far, so good.  Unfortunately, my interest lies in fairly large deviations (up to about 9 standard deviations).  All of a sudden, I start to get complex (!) answers:

> evalf(inv_erf(1-(10^(-16))));
                                 8.304785423
> evalf(inv_erf(1-(10^(-17))));
                         -3.937718724 - 4.575448791 I
 

I've tried using "erfc" instead of "erf", under the logic that it might be better at estimating the tails, but it doesn't seem to resolve the problem.  What's going on and how do I fix it?

  Thanks for any help.

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(?).

...

p1:=4*y^2+12*y-4*x*y-6*x+x^2+8

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?

Hi

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

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.

why dont any of maples 11, 12, or 13 work properly in windows seven? for example: when i click on "open a file" or "save" botton, and then it opens a window, the respective window dont show "up one level" or "create new folder" and "details" bottons above it.

Hi,

This is a student portfolio attached below. When I open the file, it says that "There were problems during the loading process. Your worksheet may be incomplete." The first time it happened, all of the graphs became blank, and the second time, only a portion of the worksheet shows up. Is there any way to retrieve the file?

Thank you...

Is it possible to set an external image-file as background in a 2d plot?
 

I am trying to define a function in terms of a solution of dsolve. I initially tried the following method:

I defined my function as:
a := 10; ode := diff( n(t), t ) + a*n(t);

Then I solve it using dsolve and store it as a function:
f:= t -> dsolve( ode, n(0) = 10);

This was syntactically wrong so I tried:
f:= t-> rhs( dsolve( ode, n(0) = 10) );

 How do I implement this sum in maple:

Sum(A[i,j],i=1..12) with j<>i

Gracias

This is what I have so far

S1:=unapply(u*FresnelS(u)+((1/Pi)*cos((1/2)*Pi*u^2))-(1/Pi),u);

C1:=unapply(u*FresnelC(u)-((1/Pi)*sin((1/2)*Pi*u^2)),u);

with(plottools);

with(plots);

u0:=sqrt(0.25);

e1:=evalf(FresnelC(u0)+FresnelS(u0)*cot((3*Pi)/8));

p1:=display(plot([FresnelC(u),FresnelS(u),u=0..u0]));

p2:=display(plot(x-e1,x=0..1,y=0..1,colour=black));

display(p1,p2);

I find that Maple leaves things like sin^2(x) + cos^2(x) as they are, which is giving me some very long and complicated looking expressions that are often just simple things.

I'm sure there must be a way of sorting this out but I can't find anything.

Also, on a more theorectical note, does anyone know why Maple doesn't do this automatically, or at least have a pre-programmed command to simplify such things?

Hi

How can add the values of a list with the list as an argument of a function. As exmaple:

f([1,2,3,4,5]);

                              15

Thanks for any help,

Dat