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If x and y satisfy (x-3)^2 + (y- 7)^2 = 64, what is the minimum possible value of x^2 + y^2?

 Jun 10, 2021
 #1
avatar+526 
-1

(x3)2+(y7)2=64                                           ...(1)

⇒ x26x+9+y214y+49=64

⇒ x2+y26x14y=6

 

∵ x and y satisfy equation (1), (x3)2  and (y7)2 are perfect squares

⇒ (x3)20                 and                    (y7)20 

⇒  x3                                                        y7

 

When x=3,  ⇒y=15

When y=7,  ⇒x=11

 

1st Case : x2+y2=9+225

                                 =234

 

2nd Case : x2+y2=49+121

                                  =170

 

Thus the minimum possible value of x2 + yis 170

 

N.B. I'm not too sure about the final answer, feel free to suggest corrections if any. 

Thank you!

 

 

~Amy 

 Jun 10, 2021
 #2
avatar+26396 
+1

If x and y satisfy (x3)2+(y7)2=64,
what is the minimum possible value of x2+y2?

 

Let the origin O=(0,0) Let the center of the circle C=(3,7) Let the radius of the circle r=64=8 Let x2+y2=r2min 

 

1. Distance between origin and center of the circle:¯OC=(03)2+(07)2¯OC=9+49¯OC=58

 

2. x2+y2=r2minrmin=r¯OCrmin=858x2+y2=r2minx2+y2=(858)2x2+y2=641658+58x2+y2=1221658The minimum value of  x2+y2=0.1476303062

 

laugh

 Jun 10, 2021

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