Use the Custom Component Template and enter this:

eq:=[y(t)=sin((1/2)*t)];
params:=[];
initialconditions:=[];
sys:=DynamicSystems[NewSystem](eq,inputvariable=[y(t)],outputvariable=[y(t)]);

Or even better, use the real expression component in the signal->sources->real tab.

Could you give an example, it works for me when i select simplify->symbolic or simplify->simplify

You don't really have a Differential Equation here, check out my solution.

eq := [F(t) = s1(t)*s2(t)];
params := [];
initialconditions := [];
sys := DynamicSystems[NewSystem](eq, inputvariable = [s1(t), s2(t)], outputvariable = [F(t)]);

-use nested for next loops to initialize your Matrix or

-write a filling procedure like this:

g:=proc(i,k) if i>k+1 then Gamma(i,k)  elif i=k then y else z end if  end proc; #just an example
Matrix(5,5,g);

Write your desired term without pressing enter afterwards:

y/2*4/3*sin(x)

Now mark with your mouse a term you want to keep, let's start with y/2. 

Select->rightclick->2-D math->Convert To->Atomic Identifier

Same procedure for remaining terms 4/3 and sin(x)

Then press enter.

Maybe there's a better method (?) 

Not sure what went wrong here, but you could try the viewpoint option.

restart:with(plots):
pointplot3d([[1,2,3],[4,5,3],[2,2,2]],color = blue, viewpoint="circleleft", axes = normal);

Hi,

use paraminfo=false

If you plot the right hand side of your equation or build the limit to infinity of it, then you see that the term is lessequal 1.2

I assume you never heard of complex numbers before, so, in your context, there is no solution for this equation.

q1:

This problem is well known, Maple doesn't show smart behaviour if the function has poles, you have to fix it manually.

q2:

Plot each function separately (p1:=plot(..);p2:=plot(..)) and combine them with display(p1,p2)

a:=exp(1):
b:=4/(3*sqrt(exp(1))):
plot([[b,t,t=0..a],[t,a,t=0..b]]);

In case you are looking for a numerical solution, there's a global optimization package available in the Application Center, try it out:

http://www.maplesoft.com/applications/view.aspx?SID=87637

restart:
d:=eta*(diff(p(r,L),L$2)+1/r*diff(r*p(r,L),r))+R*diff(p(r,L),L)=0;
pdsolve(d,build);

I see you left out a multiplication sign in EqM, this works for me:

EqP := r*P*(1-P/K)-h*P*M = 0;
EqM := M*(beta*h*P-c) = 0;
solve({EqM, EqP},{M, P});

Try to combine this with a dualaxisplot.

restart:with(Student[Calculus1]):
SurfaceOfRevolution(exp(-x), x = 0 .. 2, view = [0 .. 1, 0 .. 1, 0 .. 1], 'axis' = 'horizontal', thickness = 3, orientation = [0, 90, 90], 'distancefromaxis' = 0, 'output' = 'plot', labels = ["x", "", "y"], transparency = .1, title = "", surfaceoptions = [colour = COLOR(RGB, .2, .6, .8), style = contour, contours = 20, thickness = 5]);

Some handicraft work. Not perfect, but mine :-)

with(Student[Calculus1]):
SurfaceOfRevolution(exp(-x),x=0..2,view=[0..1,0..1,0..1],'axis'='horizontal',orientation=[0,90,90],'distancefromaxis'=0,'output'='plot',labels=["x","","y"],transparency=0.5,title = "");