no 12 tolong:) jawab dapet 20

TriGonoMetRi

sin A = 1/2
A = 150°

cos B = -1/2 √2
B = 135°

A dan B tumpul

tan² (A + B) + tan² (A - B) + 2 tan (A + B) tan (A - B)
= (tan (A + B) + tan (A - B))²
= (tan 285 + tan 15)²
= (- tan (45 + 30) + tan (45 - 30))²
= -4 tan 30 / (1 - tan² 30)
= -4/3 √3 / (1 - 1/3)
= -4/3 √3 . 3/2
= -2√3