Question

Diketahui sin A = 5/13. Jika cos A bernilai negatif, maka tan A =...

Answer 1

Sin²A + cos²A = 1
(5/13)² + cos²A = 1
25/169 + cos²A = 1
cos²A = 169/169 - 25/169
cos²A = 144/169
cos A = -12/13

sin A / cos A = tan A
tan A = 5/13 / (-12/13) = 5/13 . (-13/12) = -5/12

Answer 2

Sin A = 5/13
Untuk cos A bernilai negaitf. Maka nilai x = negatif.
Sehingga,
y = 5
r = 13
x = -12 (Phytagoras antara 13, dan 5)
Sehingga,
tan A = y/x
tan A = 5/(-12)
tan A = - 5/12