Choose the correct option and justify your choice:
(A) tan 90°   (B) 1    (C) sin 45°     (D) 0.
Choose the correct option and justify your choice:
sin 2A = 2Â sin AÂ is true when A =Â
(A) 0°     (B) 30°      (C) 45°     (D) 60°
Choose the correct option and justify your choice:
(A) cos 60°    (B) sin 60°     (C) tan 60°     (D) sin 30°.