Register to reply

Calculus graph element spotting

by Blade
Tags: calculus, element, graph, spotting
Share this thread:
Nov2-03, 07:00 PM
P: 12

a. f'(x)=0
b. f"(x)= 0
c. f'(x) = DNE
d. f = relative max
e. f = point of inflection

What I have so far (they can repeat I believe):
a. X0, X4
b. X3
c. X1
d. X2
e. X2

I'm sure something is wrong... Also, what would a f"=0 look like?
Phys.Org News Partner Science news on
Scientists develop 'electronic nose' for rapid detection of C. diff infection
Why plants in the office make us more productive
Tesla Motors dealing as states play factory poker
Nov3-03, 05:49 AM
Sci Advisor
PF Gold
P: 39,564
This really should be under "homework".

a) Yes, at x0 and x4, the tangent line is horzontal so f'= 0.

b) f"= 0 means the curve has 0 "curvature"(!) and so is very "straight" at least for a short distance. I would agree that it looks like the curve is very straight at x3 but I recommend you also look closely at x2. f"> 0 means the curve is "concave" upward while f"< 0 means it is concave downward. f"= 0 where the concavity changes.

c) Yes, there is a "cusp" at x1 and so the derivative does not exist.

d) "relative max" should be easiest of all but it surely doesn't happen at x2! Forget about derivatives and just ask yourself "where does the curve to up to the point and then back down again?"

e) A "point of inflection" is where the second derivative exists but changes sign (and so must be 0). Look at (b) again.

Register to reply

Related Discussions
Beam element vs. Finite element? Mechanical Engineering 3
Calculus area element help Calculus & Beyond Homework 4
Differences between natural element and built element? Biology, Chemistry & Other Homework 4
Train spotting, railfanning, and/modeling General Discussion 3
Spotting Fake Smiles General Discussion 18