SubArea: Sine, cosine, tangent and cotangentLevel: CProject ID: 1003076712Accepted: 1Clonable: 0Easy: 1Let \( \sin x = a \) and \( \cos x = b \). Then \( \cos(2x) \) is equal to:\( b^2-a^2 \)\( 2b \)\( 2ab \)\( a^2-b^2 \)
