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Q4
Help pleaseeeeeeee

Q4 Help pleaseeeeeeee-example-1
User Nulvinge
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1 Answer

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a. The general equation for a circle centered at
(a,b) with radius
r is


(x-a)^2+(y-b)^2=r^2

The described circle has equation


(x+3)^2+(y+2)^2=r^2

We know the circle passes through the origin. This means that the equation above holds for
x=0 and
y=0. The distance between any point on the circle and its center is the radius, so we can use this fact to determine
r:


(0+3)^2+(0+2)^2=r^2\implies 9+4=13=r^2\implies r=√(13)

So the circle's equation is


(x+3)^2+(y+2)^2=(√(13))^2=13

b. If the distance between point B and the center is less than
√(13), then B lies inside the circle. If the distance is greater than
√(13), it falls outside the circle. Otherwise, if the distance is exactly
√(13), then B lies on the circle.

The distance from B to the center is


√((-1+3)^2+(3+2)^2)=√(4+25)=√(29)


29>13, so
√(29)>√(13), which means B falls outside the circle.

User Tsutomu
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7.1k points