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USCfan
03-04-2005, 02:02 PM
Is anyone familiar with vectors?

Here's my problem: I have a position vector r, and the 2nd derivative = [-GM/(abs.value of r)cubed] x r.

According to my textbook, this means the second derivative is a scalar multiple of r, and therefore:

the 2nd derivative of r x r = 0

Can anyone explain this to me? Is it some rule dealing with vectors?
This is really urgent... I would appreciate any help. I could email you a copy of my prject, if you don't understand what I am trying to say.

battousai555
03-04-2005, 08:19 PM
Well, if you use the law of sine, cosine, and tangent all at once and multiply by the square root of a piece of pie divided by the atomic mass of adamantium this should give you whatever you asked.

fretstain
03-04-2005, 08:38 PM
could you email it to me? the_damn_echeverria@gmail.com? I haven't done this type of thing in a while but I'd like to see if I can make sense of it anyway

USCfan
03-05-2005, 05:54 AM
fretstain,
I emailed you.

Power Game
03-05-2005, 06:40 AM
I think I can do this... I'll talk to you later

fretstain
03-05-2005, 07:01 AM
for some reason it seems that my email address isn't working... could you give a better description here?

Bigmal87
03-10-2005, 02:33 PM
who'd have thought so many maths geniuses all in one thread