Diketahui : A + B = phi / 3, cos A cos B = 5/8 Tentukan hasil : sin ( A - B ) Tolong bantu ya kak ..

A + B = π/3 = 180/3 = 60°
cos (a+b) = cos a cos b - sin a sin b
cos 60 = 5/8 - sin a sin b
½ = 5/8 - sin a sin b
sin a sin b = 5/8 - ½
sin a sin b = 5/8 - 4/8
sin a sin b = 1/8
cos (a-b) = cos a cos b + sin a sin b
cos (a-b) = 5/8 + 1/8
cos (a-b) = 6/8 = 3/4
sisi samping 3
sisi miring 4
sisi depan = √(4² - 3²) = √(16-9) = √7
sin (a-b) = √7/8 = ⅛√7