WP 34S problem in solving f'(x)=0
02-17-2015, 05:55 PM
Post: #1
 lrdheat Senior Member Posts: 402 Joined: Feb 2014
WP 34S problem in solving f'(x)=0
Calculus book example function (x^2 * (x+1)^3)/((x-2)^2 * (x-4)^4).

Trying to solve f'(x)=0 proves difficult. It really requires a close narrow interval to try solve with. Using an interval as narrow as 2.4 to 2.6 produces error +inf (correct answer is ~2.46675). Keep in mind that f(x) is continuous x>2 to x<4. Using a narrower solve interval of 2.46 to 2.48 produces an inaccurate answer of ~2.4774. Using an interval of 2.44 to 2.47 is even worse, producing a zero at a nonsensical 4.0002. Even using 2.466 to 2.467 gives the 2.4774 result.

The TI 36X Pro, by contrast quickly produces a much more accurate result using single guesses such as 2.1 or 3.9.

The Prime agrees with the TI answer to 5 decimal points.

Any ideas?
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 Messages In This Thread WP 34S problem in solving f'(x)=0 - lrdheat - 02-17-2015 05:55 PM RE: WP 34S problem in solving f'(x)=0 - Thomas Klemm - 02-17-2015, 06:55 PM RE: WP 34S problem in solving f'(x)=0 - lrdheat - 02-17-2015, 07:41 PM RE: WP 34S problem in solving f'(x)=0 - Thomas Klemm - 02-17-2015, 08:10 PM RE: WP 34S problem in solving f'(x)=0 - BarryMead - 02-17-2015, 11:01 PM RE: WP 34S problem in solving f'(x)=0 - Paul Dale - 02-18-2015, 02:11 AM RE: WP 34S problem in solving f'(x)=0 - Dieter - 02-18-2015, 02:53 PM RE: WP 34S problem in solving f'(x)=0 - walter b - 02-18-2015, 05:02 PM RE: WP 34S problem in solving f'(x)=0 - Dieter - 02-19-2015, 10:38 PM RE: WP 34S problem in solving f'(x)=0 - walter b - 02-20-2015, 01:15 PM RE: WP 34S problem in solving f'(x)=0 - Dieter - 02-20-2015, 07:38 PM RE: WP 34S problem in solving f'(x)=0 - BarryMead - 02-20-2015, 07:49 PM RE: WP 34S problem in solving f'(x)=0 - MarkHaysHarris777 - 02-20-2015, 08:06 PM RE: WP 34S problem in solving f'(x)=0 - walter b - 02-20-2015, 08:08 PM RE: WP 34S problem in solving f'(x)=0 - BarryMead - 02-20-2015, 08:20 PM RE: WP 34S problem in solving f'(x)=0 - Bit - 02-22-2015, 05:04 PM RE: WP 34S problem in solving f'(x)=0 - walter b - 02-22-2015, 05:55 PM RE: WP 34S problem in solving f'(x)=0 - Bit - 02-22-2015, 06:13 PM RE: WP 34S problem in solving f'(x)=0 - walter b - 02-22-2015, 06:23 PM RE: WP 34S problem in solving f'(x)=0 - Bit - 02-22-2015, 07:10 PM RE: WP 34S problem in solving f'(x)=0 - Didier Lachieze - 02-22-2015, 09:16 PM RE: WP 34S problem in solving f'(x)=0 - pascal_meheut - 02-22-2015, 09:55 PM RE: WP 34S problem in solving f'(x)=0 - BarryMead - 02-23-2015, 07:45 AM RE: WP 34S problem in solving f'(x)=0 - walter b - 02-23-2015, 07:49 AM RE: WP 34S problem in solving f'(x)=0 - Dieter - 02-23-2015, 11:12 AM RE: WP 34S problem in solving f'(x)=0 - walter b - 02-23-2015, 07:46 AM RE: WP 34S problem in solving f'(x)=0 - Nigel (UK) - 02-23-2015, 09:24 AM RE: WP 34S problem in solving f'(x)=0 - Sanjeev Visvanatha - 02-23-2015, 01:57 PM RE: WP 34S problem in solving f'(x)=0 - BarryMead - 02-23-2015, 05:05 AM RE: WP 34S problem in solving f'(x)=0 - walter b - 02-23-2015, 07:35 AM RE: WP 34S problem in solving f'(x)=0 - Bit - 02-23-2015, 01:27 PM RE: WP 34S problem in solving f'(x)=0 - pascal_meheut - 02-22-2015, 06:20 PM RE: WP 34S problem in solving f'(x)=0 - Dieter - 02-17-2015, 11:21 PM RE: WP 34S problem in solving f'(x)=0 - lrdheat - 02-18-2015, 03:10 AM RE: WP 34S problem in solving f'(x)=0 - Dieter - 02-18-2015, 02:37 PM RE: WP 34S problem in solving f'(x)=0 - Thomas Klemm - 02-24-2015, 08:42 PM RE: WP 34S problem in solving f'(x)=0 - pascal_meheut - 02-24-2015, 09:02 PM RE: WP 34S problem in solving f'(x)=0 - Didier Lachieze - 02-24-2015, 09:04 PM RE: WP 34S problem in solving f'(x)=0 - Thomas Klemm - 02-24-2015, 09:41 PM

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