Question

If cos 60° = 1/2 and sin 60º = root 3/2 find cos 240° and sin 240".

Answer 1

cos 240 deg = -1/2 and sin 240 = - root(3)/2

Explanation:

if cos 60° = 1/2 and sin 60º = root 3/2 find cos 240° and sin 240".

we know that cos 240 = cos (60 + 180) = - cos 60 = - 1/2

cosine is negative when the angle is in the 3rd quadrant

sin 240 = sin (60 + 180) = - root(3) /2

sine is also negative in the 3rd quadrant.