What does cos 2x equal to?
We will use the concept of trigonometric formulas and identities.
Answer: The value of cos (2x) is given as cos2x - sin2x.
Go through the explanation to understand better.
Using trigonometry formulas, we have:
cos (A + B) = cosA cosB - sinA sinB
Replacing A and B with x, we get:
cos (x + x) = cosx × cosx - sinx × sinx
cos (2x) = cos2x - sin2x