Question

What is cos(2∂) equal to?

Answer 1

\[\cos (2\delta)= 2\cos^2 (\delta)-1\]

Answer 2

\[\cos ^{2}\theta-\sin ^{2}\theta\]

Answer 3

thnx! so does 2cos2(δ)−1=cos2θ−sin2θ?

Answer 4

or \(cos^2\delta-sin^2 \delta\)
or \(1-2sin^2\delta\)