Re: Implicit Differentiation

To: CALC-TI@LISTS.PPP.TI.COM
Subject: Re: Implicit Differentiation
From: RWW Taylor <RWTNTS@RITVAX.ISC.RIT.EDU>
Date: Tue, 4 May 1999 11:23:36 -0400
Reply-To: RWW Taylor <RWTNTS@RITVAX.ISC.RIT.EDU>

>  Make your equation into an expression by subtracting left side from right
>  side or right side from left side and do:
>
>  -d(expression ,x)/d(expression,y)
>
>  This will compute dy/dx.
>
>  For example:
>  3(x^2)y + 64(y^5) = e^(xy)
>  change to:
>  3(x^2)y + 64(y^5) - e^(xy)
>
>  and do:
>
>  -d(3*(x^2)*y + 64*(y^5) - e^(x*y) ,x)/d(3*(x^2)*y + 64*(y^5) - e^(x*y),y)
>
>  Good Luck
>
>  Gary Wardall

Nice clear explanation! The one thing I would add would be that it might be
helpful to store the expression being worked on under a _name_, such as t
(this is one of the great powers of the T-89/92).

Thus you would have     3(x^2)y + 64(y^5) - e^(xy) --> t

and then you could enter  -d(t,x)/d(t,y)

which is a little easier to apprehend visually and to recall when you need to
do it again (as well as being easier to match to the "book" formula when you
want to explain to someone else what you are doing).

RWW Taylor
National Technical Institute for the Deaf
Rochester Institute of Technology
Rochester NY 14623

>>>> The plural of mongoose begins with p. <<<<

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