If x and y satisfy (x-3)^2 + (y- 7)^2 = 64, what is the minimum possible value of x^2 + y^2?
(x−3)2+(y−7)2=64 ...(1)
⇒ x2−6x+9+y2−14y+49=64
⇒ x2+y2−6x−14y=6
∵ x and y satisfy equation (1), (x−3)2 and (y−7)2 are perfect squares
⇒ (x−3)2≥0 and (y−7)2≥0
⇒ x≥3 y≥7
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 + y2 is 170.
N.B. I'm not too sure about the final answer, feel free to suggest corrections if any.
Thank you!
~Amy
If x and y satisfy (x−3)2+(y−7)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=√(0−3)2+(0−7)2¯OC=√9+49¯OC=√58
2. x2+y2=r2minrmin=r−¯OCrmin=8−√58x2+y2=r2minx2+y2=(8−√58)2x2+y2=64−16√58+58x2+y2=122−16√58The minimum value of x2+y2=0.1476303062