WP 34S problem in solving f'(x)=0

02172015, 05:55 PM
Post: #1




WP 34S problem in solving f'(x)=0
Calculus book example function (x^2 * (x+1)^3)/((x2)^2 * (x4)^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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