fwd: nDer, der1 on ti85


[Prev][Next][Index][Thread]

fwd: nDer, der1 on ti85



I've got it now. nDer approximates the numerical derivative by calculating
the slope of the secant line through the points (value - little delta,
f(value - little delta)) and (value + little delta, f(value + little
delta)).  The smaller little delta is, the closer the approximation.  I was
able to reproduce your results by going into the tolerance menu (2nd CLEAR)
and changing my little delta value to 0.001.  If you change your little
delta to something like 1e-5, you should get a closer approximation to what
you want.

Don Peate
My opinions do not necessarily represent those of my employer.
-------------
Original Text
From: "Garvin Cung" <garvinc@INAME.COM>, on 5/22/98 4:34 PM:
To: smtp@netsrv1@servers[<CALC-TI@LISTS.PPP.TI.COM>]

what the difference between 'nDer' and 'der1' on the ti85 calculator?

and on this example why does it do this?

nDer(x^4-4x^3+16x,x,2)
i get the answer of 4e-6

der1(x^4-4x^3+16x,x,2)
i get the answer of 0

the answer is supposed to be zero. why is the nDer one not exaclty 0, like
der1, the way iy should be?

--garvin
_______________________________________________________
Garvin Cung
Email: garvinc@iname.com
WWW: http://www.geocities.com/ResearchTriangle/lab/2240


Follow-Ups: