how to find the numeric solution for differential equations

i need to find the numeric solution for

3y''(t)+6y'(t)+3y=1

y(0)=1

y'(0)=-1/3

i have to use : diff, cond , dsolver, simplify and subs.

[Torsten]

Look at the "dsolve" documentation. You will find many examples there similar to yours.

[Jonathan Jubran]

how can i use the cond function, i looked at the documentation and didnt find explanation

[Torsten]

Take a look at the example "Solve differential equations with conditions" under

de.mathworks.com/help/symbolic/dsolve.html

It's almost a solution for your case.

[Jonathan Jubran]

yeah i saw it, it so close for my equation but my problem is that i have to use all of these: diff, cond , dsolver, simplify, subs and symbolic vary.

thats what i cant do..

[Torsten]

I also don't know why subs and simplify should be necessary (or you did not report the exercise comletely).

What does Matlab give you as solution ?

[Jonathan Jubran]

i neet to get the numeric solution, this exercise is a part of project and they want us to use all of these functions.

the solution that matlab gives me is y(t)= exp(-t).*(t*(1/3)+2/3)+1/3. this is a right unswear for the differential equations but not the numeric solution.

[Torsten]

And what is your definition of "numeric solution" ? Are you given some specified points t where you should evaluate y(t) ? Or do you want to plot the solution over a specified interval ?

[Jonathan Jubran]

my t is

t=0:0.01:10

[Torsten]

If you named your solution ysol, then

t = 0:0.01:10;

ysolt = subs(ysol(t))

should give you the corresponding vector of function values.