Question

Lingkaran x²+y²-4x+8y=0 didilatasikan oleh [P, 3] dengan P(-1,2). tentukan persamaan bayangannya

Answer 1

Verified answer

Jawab

x² + y² - 4x + 8y = 0
(x -2)² + (y +4)² = 20
pusat (x,y)= (2, -4) , r = 20

P(a,b) = (-1,2)
K =  3

Pusat  bayangan (x', y')
x' = k (x - a) + a
x' = 3(2 + 1) - 1
x' = 8

y' = k(y-b) + b
y' = 3(-4-2) + 2
y' = -16

r' = k² (r)
r' = 3²(20) 
r' = 180

bayangan (x- 8)² + (y+ 16)² = 180