Time period, T=ω′2π Given, time period, T=ωπω′2π=ωπ⇒ω′=2ω Options (a) and (b) are incorrect. Option (c), sin2ωt=21(2sin2ωt)=21(1−cos2ωt) Hence, the angular frequency is 2ω. Option (d), 3cos(4π−2ωt) Angular frequency of SHM is 2ω. Option (d) is the correct answer.