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Michael
07/05/12 10:55am

In Response To 'Re: Re: Symbolic Computation'
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Another way is to use the ordinary function notation r[t]. Then r'[t] or D[r[t],t} will represent the derivative and can be used to set up differential equations for DSolve or NDSolve.

Or you can use r[t,x,y,phi] if you wish. Watch out, though: In this case the derivative operator D[..] yields partial derivatives. If you want to treat everything as a function of time, write r[t, x[t], y[t], phi[t]]. Try D[r[t, x[t], y[t], phi[t]], t] and see if you can parse the notation. (If confusing, try the partial derivative D[r[t, x, y, phi], x] without all the t's. What you will see is the output form of Derivative[0, 1, 0, 0][r][t, x, y, phi].)

In this form you probably ought not to set t=2 for instance. Then r[t] is the same as r[2]. You'll have to Unset or Clear t to get t back as a variable. The same goes for r, x, y, and phi.

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Subject (listing for 'Symbolic Computation')
Author Date Posted
Symbolic Computation Aditya Nanda 06/27/12 05:08am
Re: Symbolic Computation Bill Simpson 06/27/12 12:11pm
Re: Re: Symbolic Computation Aditya Nanda 06/29/12 00:12am
Re: Re: Re: Symbolic Computation Michael 07/05/12 10:55am
Re: Re: Re: Re: Symbolic Computation Aditya Nanda 07/08/12 08:43am
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