## How to I check ordinary differential equations (OD...

I have been trying to check solutions for ODE in Maple. However, there is a problem. When I go to the ODE Analyzer Assistant and enter a an ODE like: diff(y(x),x)=e^x/(y+2) and press "Solve Symbolically", I get the following message: "cannot use same name "y" to represent both a parameter and a dependent variable of the problem". I wonder if you could help. Thanx a lot! Antonio

## How do I find the Inverse of a mod?...

How do I find the inverse of a mod? eg. the inverse of 7mod27 is 4. How do I get maple to find that? Is there a simple function?

## Sum elements of a set...

Hi, I've searched for this in mapleprimes.com before registering myself in the site, and found nothing. Maybe someone can help me with this. I've generated a set of prime numbers below 1000 using: genprime := proc (n) select(isprime, {\$1 .. n)}) end proc Now I want to sum all the elements from the set genprime(1000). Is it possible? Thanks in advance, André

## Manipulating Imported Data...

Hi, I am very new to maple and have a question. I have a large number of data points in an excel file, which I am trying to overlay onto an equation to see if it fits. I can import the data fine, and the curves seem similar, however, the x values for my data points are all shifted to the left (for various reasons during the recording of the data), so the data is not on top of the curve. I would like it to be. Is there any simple way to manipulate the data in maple, say by adding a number n to all the x values, so that I don't have to go back and do it in excel? Thanks for your help. Evan

## plot vectors...

Hi I am getting a problem with plot. I am trying to plot ka (number of iterations) versus va (error norm) in this worksheet: > with(linalg):with(LinearAlgebra):with(plots):SOS:=proc(x) local n,k; n:=vecdim(x); sum(x[k]^2,k=1..n); end;NJ2Next:=proc(f,x,x0) local val,jac, xn, xn1, val1, val2; val:=eval(subs(x=x0,f)); jac:=eval(jacobian(f,x),x=x0):jac:=inverse(jac); xn:=evalm(x0-jac&*val); val1:=eval(subs(x=xn,f));xn1:=evalm(xn-jac&*val1); val2:=eval(subs(x=xn1,f)); evalm(xn1-jac&*val2); end: > NJ2:=proc(f,x,x0,N) local k, sol, valf, va, ka;sol:=array(0..N):sol[0]:=x0:va:=array(1..N):ka:=array(1..N):valf:=eval(subs(x=x0,f)): for k from 1 to N do sol[k]:=NJ2Next(f,x,sol[k-1]): valf:=eval(subs(x=sol[k-1],f)): va[k]:=evalm(log(norm(sol[k]-sol[k-1],2))):ka[k]:=eval(k):err:=evalm(norm(sol[k]-sol[k-1],2)): od: print(ka):print(va) :plot([ka,va]):end:

## (B-C)'...

I need to find out how to input the code for the above question. I know that I need to enter B minus C but how do I find the complement of a set in Maple?

Hi, I'm trying for some time to create an adaptive procedure which modify the interval of the argument of a function depending on its values. The problem is that I still can't make the "if statement" to work the way I want it. The problem is that the cycle initiate some step "p" in the beginning and it use it trough the cycle although the value of the variable "p" already is different than the initial one. After printing it out, the interval changes with the initial value and the value of p changes independently. Which implies that Maple stores the initial value somewhere and use it from there, not from the immediate memory.

## Maple and TexMacs...

Hi, I noticed that in the lastest version of TexMacs 1.0.6.5 that maple is supported. I downloaded it. It appears to run OK, but I can't get the maple mode to load. It shows up in the session selection. I would appreciate any help or pointers. My system: Win XP fully updated and patch, Maple 10 or Maple 7 or Maple V.5. Thanks Ralph Wallace K9RWW@ARRL.NET

## precalc question...

Jacob places \$20 a week into an annuity to by a new boat. He receives 6% APR and saves for 10 years. How much money did he save up to spend on his new boat?

## homework...

The two different investment offers: 6% compounded yearly, or 5.85% compounded weekly. Find the APR for each and determine which is a better investment.

## calculus...

There's initially 16 ants in the ant farm and 2 months later there were 24 ants. The box says the farm can hold a total of 1000 ants. Find the equation and determine when there will be 750 ants.

## Differential Geometry - dual...

How do I find the dual of this? Thanks for your attention! F := evalDG(E1*dt &t dx + E2*dt &t dy + E3*dt &t dz - E1*dx &t dt - B3*dx &t dy + B2*dx &t dz - E2*dy &t dt + B3*dy &t dx - B1*dy &t dz - E3*dz &t dt - B2*dz &t dx - B1*dz &t dy Jim Bowmer.