Question

Example 2 Without using trigonometric tables, evaluate :
(i) sin 18° - cos 72°
(i) sin 35° sin 55° - cos 35º cos 55°
(iii) 3 cos 80° cosec 10° + 2 sin 59° sec 31°​

Answer 1

Answer:

sin (90°-α) = cos α

as it is all will apply