
Calculus Calculus Math Forum 
 LinkBack  Thread Tools  Display Modes 
July 6th, 2017, 11:38 PM  #1 
Newbie Joined: Jun 2017 From: vancouver Posts: 3 Thanks: 0  Curve Sketching: Increasing/ Decreasing
For f(x)=x^(2/3)−x^(5/3) find the critical numbers and open intervals where the function is increasing and decreasing. Since f'(x)=(?), choose from 1/5*(53x)(x)^(1/5), (52x)(x)^(1/5), 1/3*(25x)(x)^(1/3) , 1/2*(35x)(x)^(1/3) , we see that f'(x)=0 if x=(?) and that f'(?) does not exist. Therefore, the critical numbers are (?) and (?) My answers is f'(x)=1/3*(25x)(x)^(1/3) f'(x)=0 if x=2/5 and that f'(0) does not exist Therefore, the critical numbers are (0) and (2/5), but it's not correct and I'm not sure what's wrong. Last edited by skipjack; July 7th, 2017 at 01:22 AM. 
July 7th, 2017, 01:34 AM  #2 
Global Moderator Joined: Dec 2006 Posts: 18,847 Thanks: 1568 
You identified f'(x) correctly. Try giving the critical numbers as 0 and 2/5 (without the parentheses).


Tags 
curve, decreasing, increasing or, sketching 
Thread Tools  
Display Modes  

Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
Curve Scetching: Increasing/Decreasing  soccer10  Calculus  2  July 9th, 2014 06:14 AM 
increasing and decreasing intervals  pomazebog  Calculus  3  March 21st, 2012 06:36 AM 
Curve Sketching: Increasing/ Decreasing Problem?  cokipoon  Calculus  2  March 18th, 2012 09:36 PM 
sequence increasing or decreasing  aaronmath  Calculus  4  November 6th, 2011 09:26 AM 
increasing/decreasing annuity  pomazebog  Calculus  0  December 31st, 1969 04:00 PM 