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The temperature of a point (x,y) in the plane is given by the expression x^2 + y^2 - 4x + 2y. What is the temperature of the coldest point in the plane?

 Nov 2, 2014

Best Answer 

 #2
avatar+118703 
+10

 

 

T=x2+y24x+2yT+4+1=(x24x+4)+(y2+2y+1)T+5=(x2)2+(y+1)2T=(x2)2+(y+1)25

 

Now anything squared has to be  greater or equal to zero so T has to be greater to or equal to -5 degrees. 

This will occur when x=2 and y=-1

 Nov 3, 2014
 #1
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please help me!!!!

 Nov 3, 2014
 #2
avatar+118703 
+10
Best Answer

 

 

T=x2+y24x+2yT+4+1=(x24x+4)+(y2+2y+1)T+5=(x2)2+(y+1)2T=(x2)2+(y+1)25

 

Now anything squared has to be  greater or equal to zero so T has to be greater to or equal to -5 degrees. 

This will occur when x=2 and y=-1

Melody Nov 3, 2014
 #4
avatar+130477 
0

Very nice, Melody........no Calculus required !!!!

 

 

 Nov 3, 2014
 #5
avatar+118703 
0

Thanks Chris  :))

 Nov 3, 2014

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