Choose the correct answer
is equal to
We need to find the value of:
Let
Take cosine on both sides, we get
Using property of inverse trigonometry,
cos(cos-1 A) = A
We have the value of cos x, let us find the value of sin x.
By trigonometric identity,
sin2 x + cos2 x = 1
⇒ sin2 x = 1 – cos2 x
Putting ,
Now,
Using the trigonometric identity,
sin 2x = 2 sin x cos x
Putting the value of and
,