jika sudut A dikuadran 2 sin A3/5 tentukan sin 2A

Diketahui :
90° ≤ A ≤ 180°
sin A = [tex] \frac{3}{5} [/tex]

y (absis) = 3
r (hipotenusa/sisi miring) = 5

x² = r² - y²
x = ± [tex] \sqrt{r^2 - y^2} [/tex]
x = - [tex] \sqrt{r^2 - y^2} [/tex]
*negatif karna di Kuadran II*
x = - [tex] \sqrt{5^2 - 3^2} [/tex]
x = - [tex] \sqrt{25 - 9} [/tex]
x = - [tex] \sqrt{16} [/tex]
x = -4

cos A = [tex] \frac{x}{r} [/tex] = -[tex] \frac{4}{5} [/tex]

sin 2A
= 2 . sin A . cos A
= 2 . [tex] \frac{3}{5} [/tex] . (-[tex] \frac{4}{5} [/tex])
= -[tex] \frac{24}{25} [/tex]