Evaluate:
sec2 18° - cosec2 72°
10 Likes
= sec2 (90° - 72°) - cosec2 72°
= cosec2 72° - cosec2 72°
= 0
Hence, sec2 18° - cosec2 72° = 0.
Answered By
8 Likes
sin2 40° - cos2 50°
sin 15° cos 15° - cos 75° sin 75°
sin 42° sin 48° - cos 42° cos 48°