jawab no 12 &13 pakai caranya

12||

Lim [x » 0] Tanx / Sin 2x
= 1/2

13||

x² + 5x + 4 = 0
(x + 4)(x + 1) = 0
x = -4
x = -1

x² - (X1 + 3 + X2 + 3)x + (X1+3 . X2+3) = 0
x² - (-4 + 3 + -1 + 3)x + (-4+3. -1+3) = 0
x² - (-1 + 2)x + (-1 . 2) = 0
x² - x - 2 = 0

12) Lim (Tan x)/(sin 2x) = 1/2
.... x=>0

Kalau cara panjangnya :
Lim (Tan x)/(sin 2x) . x/x . 2x/2x
x=>0

Lim (Tan x)/x . (2x)/(sin 2x) . x/(2x)
x=>0

= 1 . 1 . 1/2
= 1/2

13) x^2 + 5x + 4 = 0
(x + 4)(x + 1) = 0
x = -4 atau x = -1

Persamaan kuadrat yang akar-akarnya (x1 + 3) dan (x2 + 3) = (-4 + 3) dan (-1 + 3) = (-1) dan 2
x^2 - (-1 + 2)x + (-1)(2) = 0
x^2 - x - 2 = 0