Question

Prove that sin780
sin480
+cos240
.cos 300
=
1
÷2

Answer 1

Answer:

1/2

Step-by-step explanation:

sin780°

= sin(720°+60°)

= sin60°

= √3/2

sin480°

= sin(360°+120°)

= sin120°

=√3/2

cos240°

= cos(180°+60°)

= - cos60°

= -(1/2)

cos 300°

= cos(360°-60°)

= cos60°

= 1/2

Now

sin 780° . sin 480° + cos 240° . cos 300°

= (√3/2)(√3/2) - (1/2) (1/2)

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

= 2/4

=1/2

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Answer 2

Answer:

1/2 is answer dear friend