Diketahui nilai cos (a-b) = 2/3 dan cos a cos b = 1/2. jika a+b lancip maka nilai tan (a+b) adalah

Cos(a + b) = cos a cos b – sin a sin b = 2/3
cos(a – b) = cos a cos b + sin a sin b = 1/2
———————————————————– +
2 cos a cos b = 7/6
cos a cos b = 7/8

cos a cos b + sin a sin b = 1/2
=> 7/8 + sin a sin b = 1/2
=> sin a sin b = -3/8

tan a tan b = (sin a/cos a) (sin b / cos b)
= (sin a sin b) / (cos a cos b) = (-3/8)/(7/8) = -3/7

Simak lebih lanjut di Brainly.co.id – brainly.co.id/tugas/7518650#readmore