1. sin 28 = cos 62
2. cos 33 = sin 57
3. cos31 = sin 59
4. cos (90 - θ ) = sin θ
Complementary angles are angles that add up to give 90°. For example angle 30 and 60, angle 55 and 35.
In trigonometry, complementary angle relationship is expressed as
cos (90 - θ ) = sin θ
for example,
sin 30 = cos (90 - 30)
= cos60
1. sin28 = cos ( 90 - 28)
sin28 = cos 62
2. cos33 = sin(90 - 33)
cos 33 = sin57
3. cos31 = sin ( 90 - 31)
cos31 = sin 59
4. cos (90 - θ ) = sin θ