PGSL

x² + y² = 25

persamaan garis kutub di P(11,-2) :

11x - 2y = 25

y = (11x - 25)/2 ... (1)

subs persamaan (1) ke pers lingkaran

x² + (11x - 25)²/4 = 25

4x² + 121x² - 550x + 625 = 100

125x² - 550x + 525 = 0

5x² - 22x + 21 = 0

(5x - 7)(x - 3) = 0

x = 7/5 atau x = 3

◆ utk x = 7/5

y = (11.7/5 - 25)/2

y = (77 - 125)/10

y = -24/5

PGSL di titik singgung (7/5 , -24/5) :

x1x + y1y = r²

7/5 x - 24/5 y = 25

7x - 24y = 125

◆ utk x = 3

y = (11 . 3 - 25)/2

y = 4

PGSL di titik singgung (3,4) :

3x + 4y = 25