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Re: second and third order derivatives
This is correct
This first term is correct but the second bit is not.
But this is not right. The sign is wrong and there shouldn't be a 3 there.
And this has gone completely wrong. You've lost the 3 from the first term and the error above has made the second term wrong too.
I suggest you have a go at d2s/dt^2 again and I'll check again.
You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei