Question

Tentukan pusat dan jari jari lingkaran
x² + y² - 2x - 4y - 11 = 0

Answer 1

X² + y² - 2x - 4y - 11 = 0

a = -2
b = -4
c = -11

pusat = (-1/2A , -1/2B)
= (-1/2(-2) , -1/2(-4))
= (1, 2)

jari-jari = √1/4A² + 1/4B² - C
= √1/4(-2)² + 1/4(-4)² -(-11)
= √1 + 4 + 11
= √16
= 4 cm

Answer 2

X² + y ² + Ax + By + C = 0
x² + y² -2x -4y - 11 = 0

pusat ( -1/2 A , -1/2 B)
pusat ( 1,2)
R =  √(-1/2 A)² + (-1/2B)²-C
R = √ 1²+2²-(-11)
R = √1+4+11
R = √16 =4
jari-jarinya 4