Question

What is the exact value of sin 120° ? Use a double-angle identity.

Answer 1

`(√(3))/(2)`

Explanation:

Sine is positive in the second quadrant, so:

`\sin (240^(\circ))/(2)=\sqrt{(1-\cos 240^(\circ))/(2)} \\ \\ =\sqrt{(1.5)/(2)} \\ \\ =√(3/4) \\ \\ =(√(3))/(2)`