Question

Given the circle with equation x+ y =17

a). Determine if the points D(-4, -1) and E(1, 4) are on the circle. Show all work

b). Find the equation of the perpendicular bisector of the chord DE

c). Verify that the perpendicular bisector from part b) passes through the center of the circle

Answer 1

Explanation:

x+y=17 is NOT the equation for any circle. You have omitted the exponents. The equation for the circle should be

x^2 + y^2 = 17.

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Plug the coordinates of D into the equation.

(-4)² + (-1)² = 17, so D is on the circle.

Plug the coordinates of E into the equation.

1² + 4² = 17, so E is on the circle.

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Slope of DE = (-1 - 4)/(-4 - 1) = 1

Slope of perpendicular to DE is -1.

Midpoint of DE: ((-4+1)/2, (-1+4)/2) = (-1.5, 1.5)

Point-slope equation for perpendicular bisector:

y-1.5 = -(x+1.5)

y = -x

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Center of circle is (0,0)

0 = -0, so y=-x passes through the center.