Throughout evolution, natural selection is one source of genetic change in populations. However it is possible for a mutation to become common in a population entirely by accident through a phenomenon known as genetic drift. 

It works most strongly in small populations or dramatically fluctuating populations.  When non-lethal mutations occurs it is possible not just because of adaptation but by chance it will have more offspring than it's neighbors. 

Hi all I have the following ODE

ODE_1:=diff(w(r),r)+R*(diff(w(r), r))^3=K/r;

ODE_T_1:=collect(algsubs(w(r)=u(r)+(r-1)*(U-0)/(delta-1), ODE_1),diff(u(r), r)) ;

 and when I try to do the following integration,

eq1:=int(phi[i](r)*ODE_T_1,r=1..delta) assuming delta > 1;

it gives the following error

"

Error, (in assuming) when calling 'int'. Received: 'wrong number (or type) of arguments:

In a plot of y=x^2 how can one choose to have no tickmarks except for at given points say x=2 and x =8 and of course on the corresponding y values?

Hello. I am trying to do a project. Howerver the following code is causing Windows 7(x64) to error.

First, I get a message from mserver.exe saying: mserver has stopped working.

I click "Close the program" and I get "Kernel connection has been lost."

This is happening when I calculate the Groebner Basis by the following code. It is all right when I calculate the Groebner Basis when the problem to be solved is simpler. The memory of my computer is...

Hi, 

When I try the example of a histogram plot from the help system (under Statistics, Histogram), I get an error.

The example (entered in document mode) and error follow below.  Can someone please shed light on this?

with Statistics; with(plots):
N := RandomVariable(Normal(0, 1)):
A := Sample(N, 1000):
P := DensityPlot(Normal(0, 1), color = "Niagara Red"):
Q := Histogram(A, averageshifted = 4, style = polygon, color = "LightSlateGrey"):

Any plans of correcting the obvious problem the MaplePrimes text editor has with the inequality sign < ?
It is really quite annoying.
Everything on a line of code after < is very often discarded with the obvious effect that the code doesn't run.

Hi, I am looking for some help for a computation on Maple. I have the following objects

The sollowing sum S is a Fourier series of a non constant function. But the Maple result is a constant value of the function hypergeom. That can't be true.

S:=Sum((-1)^(1+k)*cos(2*Pi*k*x)/(-1+16*Pi^2*k^2), k = 1 .. infinity);

S=value(%);

Hello,

I am trying to add a random variable in ODE and solve it.

I chose A as the random variable.

Randomness in A will define like:

A with randomness for s in S=(-0.05,0.75) is:

A(t,s)= A`(t)+s

Where A`(t)= 0.25+ 0.0037t , if 0<= (t,365)<=182

                    0.5+ 0.0045 t  , if 182<= (t,365)<=365

I need to draw a box plot (BoxPlot(X,title="Box Plot", color=red) that shows the outliers, suspected outliers and fences. Can anyone direct me? Thanks.

The system of ODEs i am trying to analyse is just a 3d model of a ball in motion with gravity and air resistence acting upon it.

restart;

with(plots):

eq1 := diff(x(t), t, t) = -k*sqrt((diff(x(t), t))^2+(diff(y(t), t))^2+(diff(z(t), t))^2)^(n-1)*(diff(x(t), t))

eq2 := diff(y(t), t, t) = k*sqrt((diff(x(t), t))^2+(diff(y(t), t))^2+(diff(z(t), t))^2)^(n-1)*(diff(y(t), t))

eq3 := diff(z(t), t, t) = -g-k*sqrt((diff(x(t), t))^2+(diff(y(t), t...

i am doing a Q Laplace and finally summation it

however, i find an AccurateQSummation which is not like Summation

Should i use it, if not, use SumTools' summation how to simplify it?

restart;
with(QDifferenceEquations):
qexp := QPochhammer(-(-p*t), q, infinity);
f:= qexp*t;
b := subs(t=q^n,f);
QSimplify((1-q)*AccurateQSummation(b*q^n,n=-infinity..infinity));

with(SumTools):
QSimplify((1-q)*Summation(b*q^n,n=-infinity..infinity));

How I can get prd with only fifth and lower powers of x[n] in the following code?

p1:=a*x[n]+b*x[n]^3-c*x[n]^6:

p2:=d*x[n]^2-e*x^4+20:

prd:=collect(expand(p1*p2),x[n]);

Why won't evalf give me a number.  I have solved for a variable "iDS" higher up in my sheet, and want the approximate value of an element in a matrix.  this element is a function of iDS and no matter what I do, I get the function of iDS!

I really want to use Maple.  I see what it can do, but I often get "stuck" and very frustrated when I can't get it to do what I need it to do.  Sometimes when you are doing assignments, you need a number!

Been attempting this question for some time now and can't seem to get it right. 

Each time coming up with a different error.

It's part of our weekly homework, an extention question.

Write a procedure, marks, to take a student’s mark and output the appropriate grade, 

based on the following table:

mark       0-39.99          40-49.99           50-59.99          60-69.99            70+