Question

me ajudem rapideexxxx​

Answer 1

Explicação passo-a-passo:

sen²x + cos²x = 1

(1/5)² + cos²x = 1

cos²x = 1 - 1/25

cos²x = 24/25

cosx = V24/25

cosx = 2V6/5

sen75° = sen(30° + 45°)

sen75° = sen30° . cos45° + sen45° . cos30°

sen75° = 1/2 . V2/2 + V2/2 . V3/2

sen75° = V2/4 + V6/4

sen 75° = (V2 + V6)/4

cos150° = - cos30°

cos150° = -V3/2