Guys, I'm stuck on a simple silly problem.  I suppose I have one of those senior moments but in any case  ...

All I was trying to do was derive an equation from a simple word problem I made up.  Specifically it has to do with the fact that it's costing me more to buy efficient energy saving flourescent bulbs than to use those ever so energy inefficient incandescent bulbs.  But it turns out those inefficient bulbs is the cheaper route.

Basically it's a cost analysis problem.  Anyways here's how it goes. 

Hi:

I often need to change a few parameters and rerun the whole worksheet. In some cases however, some of the sections should not be executed. Is there a way to quickly comment/uncomment out a given section? If so, how?

thanks.

Hello all,

I have an ODE system called RedSys which is below and incons1 which is its initial condition.

When I want to solve this system by dsolve numeric with this command:

dsolve((convert(RedSys, set)union incons1), numeric, implicit = true);

I face an error which says :

system should be linear in leading derivative. However when check I do not see any non linearity.

could you please let me know what should I do to solve this system by dsolve/numeric?

Thanks so much,

 

Hi

I have a problem with the fact that maple not always knows the difference between pi and -pi. Try for example these three lines:

> evalf((-5-2*I)*(exp(-(.999999999*I)*Pi))^(1/2-0.8e-1*I)); 

> evalf((-5-2*I)*(exp(-I*Pi))^(1/2-0.8e-1*I));

> evalf((-5-2*I)*(exp(I*Pi))^(1/2-0.8e-1*I));

They have significantly different results where the line with the exp( - I*Pi) is interpreted as exp(I*Pi).

Is there anyway to avoid this?

I use maple 13

Thanks in advance

Best regards
Brian

In a Maplet, how do I access an expression entered into a MathMLEditor to use as a Maple expression (to plot, evaluate, simplify etc.)?

Hi.  I want to plot the function U in terms of x and y,

U :=2*diff(p(x,t),x)*diff(q(y,t),y)/(p(x,t) + q(y,t) + a[0])^2;

where

I would appreciate if anyone could solve this problem. (please see attached pdf or mw file )
The error messages is:  Error, (in ExecuteQuery) unknown API type  (I am trying to access data from a SQL server)

Download 8342_Maple is being Stupid.pdf
View file details

I used the solve command to solve for the unknown b , i do have the solution listed in the book...but when i try to solve it as follows

solve((tan(Pi/18)=(2*cot(b)*((3.4^2)*sin(b^2)-1))/((3.4^2)*(1.4+cos(2*b))+2)),b);

since maple takes values in radians(10 deg)

i get the message as "solutions may have been lost"

Am i doing anything wrong ?

Hi.

This one is rather simple. Anyway I do not get the right way to do it.

I´d like to redefine showassumed and set it to zero.

Can anyone give me an example how to do it?

Thanks.

I tried the following:

restart;
with(Statistics):
X1 := RandomVariable(Binomial(n, p)):
DARA := t->piecewise(0<t,log(t),0):

0 < n, n::posint, 0 <= p, p <= 1:
 

ExpectedValue(DARA(X1));                                        
g1 := simplify(%) = DARA(s);
k1 := solve(g1, s);
 

Hi.

Does anyone know, why or when to use the assume command as opposed to just defining the assumptions?

e.g.

instead of typing:

assume(0 < sigma);

i could just write:

0 < sigma;

right?

I did the following:

restart;
HARA := t->(alpha+delta*t)^(1-(beta)/(delta)):
0 < (beta)/(delta), (beta)/(delta) < 1:
0 < (alpha+delta*t);
 

Now Maple prints the last assumption like:

0 < alpha*t

thus assuming that delta must equal 1.

 

Why?

 

Thanks for helping.

 

I am new to Maplet programming and came across this problem while looking trying to build a simple application. Running the code results in: "Error, (in Maplets:-Tools:-CleanUp:-SetOption) the target `("REF")("enabled")` refers to a non-existant element" I am at a loss for why this is the case. From what I read, I am doing this right, but if anyone can see the problem... I would appreciate the help.

I am not able to use colors flexibly in contourplot3d. So, I am trying another way to get my plot. But I am not exactly getting my result. This is what I am trying to do. I need help with these three steps. 1) For Latitude from -10 degrees to 10 degrees and longitude from -30 degrees to 30 degrees, I need to calculate aa:=1.4*cos(latitude)-2*sin(longitude). 2)The above value of 'aa' gives color. (eg. if aa<><><>3 color= red etc) 3) Then plot this point with color from step 2 at (x,y) given by