Question

prove that sin120 cos330+cos240 sin330=1​

Answer 1

Step-by-step explanation:

=(3/2)+(1/4)

=3+1/4

=4/4

=1Sin120= sin(90+30)=cos30 = √3/2

cos150=cos(180–30)=-cos30= -√3/2, since cosx is negative in second and third quadrants

cos240 = cos(180+60)= -cos60 = -0.5, the above reason

sin330=sin(360–30)= -sin30 = -0.5, as sinx is negative in the third and fourth quadrants

So the value of the given question is

(√3/2)*(-√3/2)*(-0.5)*(-0.5)

=(-3/4)*(1/4)

=-3/16