Question

if tan 20 = 0,325
cos 20 = 0,951

a) sin 20?
b) cos 160?

Answer 1

tan 20° = sin 20° / cos 20°

=> sin 20° = tan 20° · cos 20°

sin 20° = 0.325 × 0.951

sin 20° = 0.309

And,

cos 160° = cos (180° - 20°)

cos 160° = - cos 20°

cos 160° = - 0.951