My Math Forum  

Go Back   My Math Forum > College Math Forum > Calculus

Calculus Calculus Math Forum


Reply
 
LinkBack Thread Tools Display Modes
January 28th, 2013, 01:38 PM   #1
Newbie
 
Joined: Jan 2013

Posts: 3
Thanks: 0

Convex, concave or neither is convex/concave?

So I had this exam question about if this function was concave, convex or nor concave nor convex...

e^(x-y)

My first guess I would use the maxima/minima theorem

Like when

A=f''xx = e^(x-y)
B=f''xy= -e^(x-y)
C=f''yy= e^(x-y)

So AC - B = 0 ( (e^(x-y)) * (e^(x-y)) - (-e^(x-y))^2)= 0 so nor convex nor concave right?
Brazen is offline  
 
Reply

  My Math Forum > College Math Forum > Calculus

Tags
concave, convex, convex or concave



Search tags for this page
Click on a term to search for related topics.
Thread Tools
Display Modes


Similar Threads
Thread Thread Starter Forum Replies Last Post
Proving concave functions and convex sets johnathanfisk Real Analysis 0 May 28th, 2013 06:32 PM
Concave Function of a Convex Function swagatopablo Algebra 0 October 10th, 2012 11:49 PM
limits of x for differentiation , concave up & concave down zunayeed Calculus 1 August 3rd, 2011 09:37 AM
convex combination of closed and convex sets frederico Real Analysis 0 April 6th, 2009 12:31 PM
Monotony, Concave Up/Concave Down problem morph Calculus 2 January 22nd, 2008 08:27 AM





Copyright © 2019 My Math Forum. All rights reserved.