Did i take this derivative of the vector right?

[mr_coffee]

Hello everyone, i just want to check to see if this derivative of the vector is right, I can't access maple and i don't have a ti-89 so i can't check!
here it is:
http://show.imagehosting.us/show/798939/0/nouser_798/T0_-1_798939.jpg

 

[Pengwuino]

Check that domain section...

 

[mr_coffee]

ahh should be r >0 right? is the derivative right too? thanks!

 

[Pengwuino]

No. Look what happens to the i vector when you have t=3

 

[mr_coffee]

oh f word...
can i say, t < 0?

 

[Pengwuino]

Well, the thing is that it can go above 0... but how far?

Start looking at the equations and ask yourself where each one has a valid result. For example, the i component can be t=<2