## Force collect an almost common factor...

Hello everyone,

I like to force following:

a/(a+b) --->  1/(1+b/a)

I know that collect is a powerful tool that is actually capable of doing such things. In a similar (old) thread, it was suggested to use a function in the last part like

collect(expression, varialble, (x->something)@factor)

but I don't understand what exactly this means. Any help?

another related question is, is the collect command available as right-click option?

## Calculate percentage change in a solution?...

I have a differential equation having a parameter say 'a'.

If I increase 'a' by 10%, got change in the solution as well.

How to calculate change in percentage in the solution?.

Thanks

## Does maple 16 work with Visual studio 2012?...

Does maple 16  work with Visual studio 2012?

## full evaluation needed...

Check these 3 code lines. a,b are some reals.

s:=a/b

g:=(a,b)->s

g(1,2)

yields a/b

Is it possible to make Maple spit out 1/2, maybe with some default setting command? I still want to keep the function call format g() , so no eval(g(),...)

## Shortest path problem...

`Modify the shortest path problem by rewriting a procedure Path, non-Recursion that print out the shortest path from a to e base on the information from  setShortestDistNode input:  destination "e" and setShortestDistNode output:  path : a -> b -> d -> e the total cost: 9hint: copy everything that we did in shortest path problem, and rewriting a procedure Path, with while loop `
`can...`

## Procedure that removes repeating elements...

`write a procedure to remove all repeating elements from a given listinput:     a list with  repeating elements, such as [1, 5, 4, 1, 2, 4, 5, 1, 6]output:   a list without  repeating elementsnote: use list as your only structual datatype, can't convert it to set`
`hint:  you may use maple function has, no srting needed.`
`can someone help me on how to write this ? thank you`

## Procedure with empty plot...

`restart:with(plots):`
`Nb:=0.5:Nt:=0.5:G:= 2:B:= 2:beta:= .2:Q:=2: alpha:= 2:`
`de := diff(alpha*f(y), y, y, y, y)+G*(diff(theta(y), y, y))+B*(diff(phi(y), y, y))`
`+6*beta*(diff(f(y), y, y))*(diff(f(y), y, y, y))^2+3*beta*(diff(f(y), y, y, y, y))*`
`(diff(f(y), y, y))^2 = 0, diff(theta(y), y, y)+Nb*(diff(theta(y), y))*(diff(phi(y), y))`
`+Nt*(diff(theta(y), y))^2 = 0, diff(phi(y), y, y)+Nb*(diff(theta(y), y, y))/Nt = 0:`

## Win7 and Compiler...

`I installed M16 32 Bit on my new machine with Win7 64 Bit.But the following results in crushing mserver.exe:  tmp := proc( x :: float ) :: float; 2.3 * x end proc:  cp:=Compiler:-Compile(tmp);with system info below. Do I have to set certain rights for the compiler or define a specific working directory?The FAQ http://www.maplesoft.com/support/faqs/results.aspx?search=compiler does not help me.Dito http://www.maplesoft...`

## Disconnect in a curve??...

I adopted the approach suggested in an earlier post (http://www.mapleprimes.com

/questions/137320-Plotting-A-System-Of-Ode) for the known results,

but some part of curve is missing.

The output I got is

## Incorrect use of independent variables (PDE)...

`restart:with(PDEtools):with(plots):declare(u(x,y,t)):PDE1:=diff(u(x,y,t),t\$1)+a*u(x,y,t)*diff(u(x,y,t),x\$1)+diff(u(x,y,t),x\$3)+`
`b*diff(u(x,y,t),y\$2)=0;Sol1:=pdsolve(PDE1);`
`Test1:=pdetest(Sol1,PDE1);params:={a=6,b=1,_C1=1,_C2=1,_C3=1,_C4=1};`
`Sol2:=subs(params,Sol1);`
`plot3d(subs(t=1,rhs(Sol2)),x=-10..10,y=-10..10,axes=boxed,grid=[50,50],`
`style=patchnogrid,shading=Z,orientation=[-40,50]);`

## getting traditional colors from VolumeOfRevolution...

The new VolumeOfRevolution command in the Student[Calculus1] package has lots of nice features for controlling the output (Riemann sum, 3D plot, animation, inert integral, numerical approximation, ...).

The default colors for the plot are not very appealing. Not only is the pink easily washed out by a projector in a moderately light room, but the detail is missing. To illustrate, consider

`with(Student[Calculus1]):VolumeOfRevolution(2-x^2, x, x=0..1, output=plot );`

## How to extract data from a contour plot?...

restart:with(plots):

eq := diff(f(eta), eta, eta, eta)+.11-(diff(f(eta), eta));

bc2 := f(0) = 0, (D(f))(0) = 1, (D(f))(10) = .1;

dsolve({eq,bc2}):

F1:=evalf(rhs(%));

contourplot(x*F1,x=-3..3,eta=-0.2..0.2);

I need to get the data from the above plot in a .txt file.

Thanks

## Computation time and assigning issues...

Hello,

I am trying to solve 9 non linear equations in 3 do loops(program attached without loop) and I am using digits:=20; for computing 10 values its takes around 5 minutes. I need to compute around 18000 such values for a plot. It might take several days for this. Is there any mistake in my code which is taking it so long to run or is it just the complexity of the equations.

Secondly, I am trying to compute some calculations to...

## Tensor with indices in Physics package Maple 16...

Can I create an tensor in the Physics package in Maple 16 with a free index like i=1..N:

A[mu,1]:=A[mu]

A[mu,2]:=B[mu]

.

.

.

and so on? The index is not one of the type gauge, spacetime or spinor.