Question

O seno do arco de medida 255° é igual a: (1,0)
A) √2 – √6/4
B)-√2 – √6/4
C)√2 + √6/2
D)√2 – √6/2
E)√2 – √6/6

Answer 1

Cosseno 225 = Sen(270 - 255) = -Sen 15

>-Sen 15 = - Sen (45 - 30)
.................= - (\/2/2 x \/3/2 - \/2/2 - 1/2)
.................= - (\/6/4 - \/2/4)
.................= - \/6/4 + \/2/4
................= \/2/4 - \/6/4

A resposta e a alternativa (A)