Khẳng định nào sau đây đúng

\({\rm{sin}}\left( {2030a} \right) = 2030{\rm{sin}}a.{\rm{cos}}a\);

\({\rm{sin}}\left( {2030a} \right) = 2030{\rm{sin}}\left( {1015a} \right){\rm{.cos}}\left( {1015a} \right)\);

\({\rm{sin}}\left( {2030a} \right) = 2{\rm{sin}}a{\rm{cos}}a\);

\({\rm{sin}}\left( {2030a} \right) = 2{\rm{sin}}\left( {1015a} \right){\rm{.cos}}\left( {1015a} \right)\).