## Select a sqrt from an expression...

Given an expression such as: k:=sqrt(x)+sin(x)+exp(x)+3+sin(y); what is the most effective way of extracting the part of k that contains any/all square roots? I've played around with selectfun and select, but just can't seem to get anything out of them...I can seem to pick out any trig and exp type functions, but not the sqrt?

## Integration incorrect with assume command, correct...

In trying to answer a question for one of my students I found the following strange behavior: The probability density for the time t that standard Brownian motion started from 0 first hits the value a > 0 is: f := a*exp(-a^2/(2*t))/(sqrt(2*Pi)*t^(3/2)) Then the expected value of this hitting time is: int(t*f, t = 0 .. infinity) Maple 11 gives the answer signum(a)*infinity which is correct, as long as one understands that signum(a)=1. However, if one now assumes that a > 0 and integrates, then the answer is incorrect:

## Can you help me with Bessel functions?...

a:=evalf(sum((-1)^n*BesselK(-2*n+1,1)*BesselJ(2*n,-1),n=-infinity..infinity)); a1:=evalf(sum((-1)^n*BesselK(-2*n+1,1)*BesselJ(2*n,-1),n=-100..100)); a := 0.02456830552 a1 := 0.5233322456 Can you undestood me Why a<>a1? And how it calculated in Maple 10? Thank you before!

## trigonometric function to sinc function...

Hi - Does anybody know of a command that can convert all trigonometric functions in an expression into sinc functions (not hyperbolic). Something like convert,sincos but for sinc function. Thanks.

## Dragging curves in maplets?...

Hi, I was wondering if it is possible to drag a curve from one plotter to another in a maplet? Is there a way to do this with Java/OpenMaple? Regards, Art

## multiple plots...

Hi i am currently using maple 10 student edition and is trying to reduce the number of graphs i need to display. here are the following plots i have 1) implicitplot(x^3+3*x*y+y^3 = 1, x = -2.5 .. 2.5, y = -2.5 .. 2.5) 2)display([polygon([[-1, -1], [1.50322, -.503215], [-.503215, 1.50322]])], scaling = constrained) 3) (plots[display])((plottools[line])([-1, -1], [.5, .5]), color = red) is it possible to combine all 3 plots into one? or even 2. another question is in plot number 2 I drew a triangle. is it possible to make it show the angles of the triangle as well as the length of the sides on the plot?

## Expanding trig functions...

Can anybody help me how to convert (in both directions) the sums of trig functions like sin A + sin B = 2 sin ½(A + B) cos ½(A - B) Simple expand and combine commadns do not work in this case.

## Solving equations...

Hey guys, I want to solve an equation using maple.. for example, say I have the values for radius, length, and resistance.. and i want to find the value for conductivity, how would i do this? Assuming the values for radius, length, and resistance are 1, what program would I write to get maple to solve for conductivity. the equation is p=(L/RA) where p is conductivity, L is length, R is resistance, and A is radius... i know these are not the real names for the variables, but this is an example. I was thinking eq:= p=L/RA; L=1;R=1;A=1; Solve(eq,p); However this is not working. Any help for a maple newbie?

## Using The "commutator" Command In The "tensors" Pa...

Can the commutator command in the tensors package be used with tensors of rank greater than 1 ? I recently tried to prove the jacobi identity using the 2 x 2 Pauli Matrices, that I created as arrays, but kept getting an error message saying something about the improper rank, of the arguments of the commutator command. I noticed in the help pages that the arguments of commutator must be of rank 1. I also tried all combinations of covariance and contravariance of the pauli matrices, but nothing worked. Can anyone help with this ? Is there any way to get around this ? thanks, v/r,

## static plots in JSP...

Hello, I am trying to draw a static plot in JSP (without java needed on client ). I am sure that the command is OK, I wrote it according the example in manual.
<maple:statement type="plot" height="200" width="400">plot(x*x,x=-1..1,y=0..1)</maple:statement>
But this error appears in browser:
MapleNet JSP Error Error in maple:statement (Reference # 1196078978052) cannot_convert_results Please try again.
I looked into logs and there is an error:
... 2007-11-26 13:09:37 StandardContext[/maplenet][org.apache.jasper.runtime.PageContextImpl@6e82254d] maple: statement: to Maple -plot(x*x,x=-1..1,

## How do I use Maple for taking notes(symbol entry w...

Hi, I've been pondering using Maple 11 to take notes in a class. My backup plan is to use Lyx or a Latex front end. When I click on a symbol in the menu the symbol is inserted typeset as if it had been handwritten. When I enter certain symbols such as "forall" and "exists" they show up as text rather than the symbol. I've tried the "convert to 2D math" option but that has no effect. Is there a way to enter symbols and have them typeset by typing them out(like \forall ) or must I click on the buttons for it to work? Thanks.

## Parsing a value to Int, arrays in procedures...

First a thank you is in order for gkokovidis for helping me with a problem earlier. The brief story is I am trying to animate a certain box on a 30 degree slope. In order to put it together, I need to be able to turn it into a an array. In order to set an array, I need to be able to parse a certain value to an integer. Let me show you the code thus far. ``` restart: with(plottools): with(plots): c := rectangle([0,1], [1,0]): d := rectangle([1,2], [2,1]): e := rectangle([2,3], [3,2]): f := rectangle([3,4], [4,3]): g := rectangle([4,5], [5,4]): IPLaunch:=proc(v0,m) local g,a,t,S,h,T: ```

## 2D Animation: Animating A box on an angle....

Please, take a look at the following work sheet for maple 11.01: View 6742_test.mw on MapleNet or Download 6742_test.mw It contains two similar documents blocks with functional operator assignments: ` f:= proc (x) options operator, arrow; 3*x end proc` and ` g := proc (y) options operator, arrow; 3*y end proc` One is collapsed another is not and this is the only principal difference between them. Now the output in collapsed document block is `x -> 3 x` while in expanded `g := y -> 3 y`.