Question

1- Calcule o sen 15° (60° - 45°)


2- Monte a tabela dos angulos notáveis

3- Calcule o cos de
a) 75°
b) 15°

Answer 1

1-
Sen(a-b) = sena.cosb - senb.cosa
Sen(60-45)= sen60.cos45 - sen45.cos60
Sen(15) = √3/2.√2/2 - √2/2.1/2
sen15 = √6/4 - √2/4
sen15 = (√6-√2)/4 ✓