Question

Find the value of sin 330.cos 120+cos 210.sin 300?

Answer 1

Alternatively we may write as follows----

                         sin330= -sin30 = -(1/2)
                         cos120=-cos60 = -(1/2)
                         cos210= -cos30 =(-√(3)/2)
                          sin300=-sin60 = (-√(3)/2)

Putting these values in below equation, we get---------

sin 330.cos 120+cos 210.sin 300

=(-1/2)(-1/2) + (-√(3)/2)(-√(3)/2)

= 1/4+3/4

=1

Answer 2

Answer:

Step-by-step explanation:

=Sin300.cos120 + cos210.sin300

=Sin(360-330).cos(90+30) + =cos(270-210).sin(360-300)

=(-sin30).(-sin30) + (-sin60).(-sin60)

=Sin²30+sin²60

=(1/2)²+(√3/2)²

=1/4+3/4

=4/4

=1