Tentukan pusat dan jari jari lingkaran 4x^2+4y^2-8x+16y+19=0

jawab


4x^2 + 4y^2 - 8x + 16 y = -19
x^2 + y^2  - 2x + 4y = - 19/4
(x - 1)^2 + (y +2)^2 = -19/4 +1 + 4 = 1/4
p(1, -2)
r= √1/4 = 1/2