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October 6th, 2007, 03:43 PM  #1 
Newbie Joined: Oct 2007 Posts: 3 Thanks: 0  Prove that... ((PLS HELP))
Hi there, please, can someone help me to prove this inequality? "Prove that: (ab+ac+bc1)²>or=(a²+1)(b²+1)(c²+1) for every real numbers a, b and c." Thanks in advance. 
October 7th, 2007, 06:26 PM  #2 
Global Moderator Joined: Dec 2006 Posts: 20,484 Thanks: 2041 
(a² + 1)(b² + 1)(c² + 1) = (ab + ac + bc  1)² + (a + b + c  abc)², as someone else pointed out on the other forum where you posted this problem.

October 8th, 2007, 06:48 AM  #3  
Senior Member Joined: Dec 2006 Posts: 1,111 Thanks: 0  Quote:
 

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