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+

For a math class, we have to create a roller coaster. Part of the coaster consists of two banked curves. I've tried looking it up but Maple isn't very clear on how to create the. So, how do you create banked curves in Maple?

> x[n]:=e[n]+w;
> f(w):=0;
> fxn:=convert(series(f(x[n]),e[n]=0,10),polynom);

How I can rewrite fxn so that every (1/k!)f^(k)(w)/f^(1)(w) for k=2,3,... is automatically replaced with c_{k}?

Here bracketed superscript denotes order of differentiation.

Hi

i know to make an asymptotic expansion one uses asympt(1+x,x); how do you make it go to -infity rather than plus infinity?

How I can omit O() term in a series expansion so that the expansion remains a simpler polynomial only?

I have a function

where mu=-19.89674583,sigma=2.35671007 and k=2.475778082 are parameters

I calculate the integration of s with respect of x on intervals of 

I'm solving a system of ordinary differential equations numerically, I used the dsolve(system,numeric) to do it. I have also plotted the solutions. Now I want to know where does this solution cross zero and use this value for later computations, is there a way to do it? 

This question is, as I think, equivalent to how to find the roots for a curve expressed in numerical arrays.

Thank you!

How to determine the volume of a sphere from its cross-sectional area, if we rotate it with center the diameter?

Gracias

I'm having trouble with the function G:=(n)-> 3 +2n-sum(sum(f(h), a=1..floor(m/2)), m=1..n) with base case G(0):=3, where h:=2a and f(h):=sum('f(2m)*3m, m=1..(h/2 -1).

For G(1), G(2) etc I get "Error, (in type/satisfies) too many levels of recursion" , note f(h) works properly. So I think the error is from the double summation. Any ideas what may be the problem?

Any help would be greatly appreciated.

Hello

I was trying to place the legend of a plot inside of it, and skimming through this site I found a solution based on a textplot, something like this:

plot(loglogplot1, loglogplot2, loglogplot3, loglogplot4): #just the functions to plot

textplot({[placement, 'typeset'(beta=10^-9 ),color=black],[...],[...],[...]}): #just the value of beta changes

plot([placement],x=4..6,color=[black,blue,red,green],linestyle=[solid,dash,dot,dashdot]):

Hi comrades. I am trying to do something like this
plot3d( fsolve( x^2 + a*x + b =0, x), a=0.1..5, b=0.5..3);
(this is not what I'm actually doing, I want to make a 3D plot of a more complicated function that uses fsolve, so don't just suggest the quadratic formula!).

I.e. plot the root of an equation as a function of some parameters in the equation.

It's not plotting because it says
"Error, (in fsolve) {a, b} are in the equation, and are not solved for"