C-09-Q148mediumsingle_mcqsin75∘\sin 75^\circsin75∘ equals—acos15∘\cos 15^\circcos15∘bsin15∘\sin 15^\circsin15∘ctan15∘\tan 15^\circtan15∘dcot15∘\cot 15^\circcot15∘ব্যাখ্যাSince 75∘75^\circ75∘ and 15∘15^\circ15∘ are complementary (75∘=90∘−15∘75^\circ=90^\circ-15^\circ75∘=90∘−15∘), the cofunction identity gives sin75∘=cos15∘\sin 75^\circ=\cos 15^\circsin75∘=cos15∘.