Question

27. The value of (cos 330° + sin 660° +
sin 150° cos 120°) is:​

Answer 1

Answer:

(cos330 +sin660+sin150cos120)

=cos(360-30)+sin(2*360-60)+sin(180-30)cos(90+30)

=cos30 -sin60+sin30(-sin30)

=√3/2-√3/2-(1/2)^2

=-1/4

Answer 2

Answer:

1/4

Step-by-step explanation

You can also go to Symbolab trig calculator

and it will do what I just did for you on my scientific calculator with steps involved

(cos330 +sin660+sin150cos120)

=cos(360-30)+sin(2*360-60)+sin(180-30)cos(90+30)

=cos30 -sin60+sin30(-sin30)

=√3/2-√3/2-(1/2)^2

=-1/4