I encountered a problem with a simple subs in Maple 15.01:

Q:=1/(a*l);

subs(a*l=t,Q);

This fails to perform the substitution and gives 1/(a*l) instead of 1/t.

However, it seems to work in certain form, for example:

Q:=exp(a*l);

subs(a*l=t,Q);

produces exp(t) correctly.

Furthermore,

Q:=1/(a*l)*exp(a*l);

subs(a*l=t,Q);

gives exp(t)/(a*l). Strangely, the substitution in the exponential is correct...

I am trying to maximize a non-linear function f with respect to variables {a,b}.

Could any one suggest a smarter way of entering this into Maple please, as I am not able to get an answer.Thank you.

The function (shown below) also has the parameters {c,H} in it and I have the constraint:

CONSTRAINT:______________0

My Function f:

(256 a^4 (4 c - H) + (1604 c - 10385 H) H^4 -
   60 b^3 H (56 c + 177 H) + 6 b^2 H^2 (-708 c + 1663 H) +

Hi,

I'm trying to use powsolve to give me the power series of a differential equation. It's been working wonderfully, afaik, but once I put in exp(x) it refuses to run. Here's my code:

 >with(powseries);

>a := powsolve(diff(y(x), x, x)+y*exp(x) = 0, y(0) = 1, (D(y))(0) = 2); tpsform(a, x)

and the error I'm getting:

Error, (in powseries:-powsolve) final value in for loop must be numeric or character

> restart; with(DEtools);
> ED1 := diff(y(x), x) = sen(y)+cos(x);
print(`output redirected...`); # input placeholder
                    d                        
                   --- y(x) = sen(y) + cos(x)
                    dx                       
> dfieldplot(ED1, y(x), x = 0, y = 0, title = `Ejemplo 1`, color = sen(y)+cos(x), arrows = almit, title = figura*(diff(1, x)));
%;
Error, (in DEtools/dfieldplot) invalid range for independent variable

See attached.  I have stared at this long enough to the point I need some FRESH eyes on this.  Why does MAPLE return FALSE on the last 2 statements

Solve the equation y"-4y=lnx ?

Hello!

if anyone can help ill be greatful!.

i have his equation:

eq1:=(8/x)=tan(7*x/50)

of course  there are infinite analitical solutions....   solution = F(x)+Pi*n, n=1....infinity

what i want to do, is to define N. and then,  to put the first N solutions of the equation into a Vector called X,

so X[1]=F(x)+1*Pi

X[2]=F(x)+2*Pi

...

X[N]=F(x)+N*Pi

can someone help?

Hi,

How can we re-initialize a multi-body system, for example a three link pendulum, based on measurements obtained from various sensors? Can we generate a modelica custom component which has inputs from various sensors and the output is the re-initialized states for the multi-body system?

Thanks for your help....

When exporting plots some labels are occasionally cropped. This is true when exporting via the context menu or with plotsetup('gif', etc.) for instance (plotsetup also drops the third label in 3D plots, the context menu keeps it).

I discovered that scaling the plot from the context menu can help: is there a programmatic way to control the plot scale?

From the context menu: Manipulator -> Scale, the plot can be rescaled to ensure that all...

Hello,

i want to solve the following for q[b], theta is a symbolic coefficient. When I use the solve command it produces a RootOf that i cannot handle by using either allvalues or evalf. I can't use fsolve since there is theta 

In the previous question, we discussed a workaround for evaluating a multi-variable integration. 

For the following example 

> g := (e1, e2, e3) -> piecewise(e1+1.200000000 <= e2 and e3-2.400000000 <= e1, evalf(64.00000000*exp((-1)*8.000000000*e1^2)*exp((-1)*8.000000000*e2^2)*exp((-1)*8.000000000*e3^2)/Pi^2), 0);
> 
> evalf(Int((x, y, z) -> g(x, y, z), [-2 .. 2, -2 .. 2, -2 .. 2]), 3);

Maple could start execution and do the computation.

When an integration is successfully evaluated numerically, a float number is returned, otherwise the unevaluated expression is returned. I'm wondering whether Maple has a utility function which simply takes in whatever the integration evaluation gives and return a boolean flag indicating whether it is unevaluated or is a floating point result? 

Hi, I got a problem that "Warning, solutions may have been lost" when I solve 

eqns := {a+r*t*ln(l)+(1-l)^2*m-b-r*t*ln(s)-(1-s)^2*n = 0, a+r*t*ln(1-l)+l^2*m-b-r*t*ln(1-s)-s^2*n = 0}

vars := {l, s}

solve(eqns, vars)

Why?

hi

i write the followinf code in maple

eq1:= f'''(x) - f'(x)

is this posible in maple that i worte the above command like this

Linear:= d3/d(x) - d/d(x)

eq1:= linear (f)

thanks for youe attention in advance