February 12th, 2016, 03:24 PM  #1 
Newbie Joined: Feb 2016 From: Oregon Posts: 19 Thanks: 0  Critical Value Help
Let f(x) = 8√x − 6x for x > 0. Find the open intervals on which f is increasing/(decreasing). Then determine the xcoordinates of all relative maxima/(minima).
Last edited by skipjack; February 12th, 2016 at 11:12 PM. 
February 12th, 2016, 04:00 PM  #2 
Math Team Joined: Jul 2011 From: Texas Posts: 2,980 Thanks: 1573 
$f(x) = 8\sqrt{x}  6x$ what did you get as the derivative? 
February 12th, 2016, 08:14 PM  #3 
Newbie Joined: Feb 2016 From: Oregon Posts: 19 Thanks: 0 
I got f$\,'\!$(x) = 4x  6 as the derivative.
Last edited by skipjack; February 12th, 2016 at 11:04 PM. 
February 12th, 2016, 08:23 PM  #4 
Math Team Joined: Dec 2013 From: Colombia Posts: 7,671 Thanks: 2651 Math Focus: Mainly analysis and algebra 
Not ${4 \over \sqrt x}6$?

February 13th, 2016, 04:11 AM  #5 
Math Team Joined: Jul 2011 From: Texas Posts: 2,980 Thanks: 1573  

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