Difference between revisions of "AoPS Wiki talk:Problem of the Day/June 21, 2011"

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{{:AoPSWiki:Problem of the Day/June 21, 2011}}
 
{{:AoPSWiki:Problem of the Day/June 21, 2011}}
 
==Solution==
 
==Solution==
{{potd_solution}}
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(2x+3y)^2 + (3x-2y)^2 = 13(x^2+y^2)=26
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Hence (2x+3y)^2 <= 26 or 2x+3y = sqrt(26).
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If 3x-2y=0 and 2x+3y=sqrt(26), then 2x+3y attains this maximum value on the circle x^2+y^2=2.

Revision as of 20:26, 20 June 2011

Problem

AoPSWiki:Problem of the Day/June 21, 2011

Solution

(2x+3y)^2 + (3x-2y)^2 = 13(x^2+y^2)=26 Hence (2x+3y)^2 <= 26 or 2x+3y = sqrt(26). If 3x-2y=0 and 2x+3y=sqrt(26), then 2x+3y attains this maximum value on the circle x^2+y^2=2.