C-09-Q192mediumsingle_mcqWith the same data, B=?B = ?B=?a30∘30^\circ30∘b45∘45^\circ45∘c60∘60^\circ60∘d15∘15^\circ15∘ব্যাখ্যাFrom cos(A−B)=1\cos(A-B)=1cos(A−B)=1 we get A=BA=BA=B, and sin2A=32\sin 2A=\tfrac{\sqrt3}{2}sin2A=23 gives A=30∘A=30^\circA=30∘. Hence B=30∘B=30^\circB=30∘ as well.