diketahui tan a° = 1/2 dan tan b° = 1/4 ( 0

jawab
tan A = 1/2  → tan A = sin A/ cos A
sin A /cos A = 1/2
misal sin A = 1(x) , cos A = (2x)
sin² A + cos² A + 1
(x²) +(2x)² = 1
5x² = 1
x² = 1/5
x= √1/5 = 1/5 √5
sin A = x= 1/5 √5
cos A = 2x = 2/5 √5

sin 2A = 2 sin A cos A = 2 (1/5 √5)( 2/5 √5)
= 4/25 (5)
= 4/5