Answer:
Step-by-step explanation:
The idea here is to get the left side simplified down so it is the same as the right side. Consequently, there are 3 identities for cos(2x):
,
, and
We begin by rewriting the left side in terms of sin and cos, since all the identities deal with sines and cosines and no cotangents or cosecants. Rewriting gives you:
Notice I also wrote the 1 in terms of sin^2(x).
Now we will put the numerator of the bigger fraction over the common denominator:
The rule is bring up the lower fraction and flip it to multiply, so that will give us:
And canceling out the sin^2 x leaves us with just
which is one of our identities.