Question

Faça o cos e seno de 195°​

Answer 1

Cos195° < 0

= — Cos ( 195° — 180° )

= — Cos( 15° )

= — Cos ( 45° — 30° )

= — [ Cos45° • Sin30° + Sin45° • Cos30° ]

= — [ √( 2 )/2 • 1/2 + ( √2 )/ • ( √3 )/2 ]

= — [ √( 2 )/2 ( 1/2 + (√3 )/2 ) ]

= — [ ( √2 )/2 ( 1 + √3 )/2 ]

= — [ ( √2 + √6 )/4 ] .