Coordinate Geometry 2

Question 1

Equation of circle

Answer 1

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

(a,b) is midpoint
r is radius

x^2 + y^2 + 2fx + 2gy + c = 0
complete the square for eq of circle

Question 2

Angle in semicircle is right angle

Perpendicular line from centre to chord bisects the chord

Answer 2

Question asks to find eq of cirumcircle of triangle, given the vertices

Question 3

Radius is perpendicular to tangent at that point

Answer 3

Questions asks to find eq of tangent