Definitions [2]
Complementary angles: When the sum of the measures of two angles is 90°, the angles are called complementary angles. Example, 30° + 60° = 90°.
Complementary angles: When the sum of the measures of two angles is 90°, the angles are called complementary angles. Example, 30° + 60° = 90°.
Formulae [1]
Formula: Trigonometrical Ratios of Complementary Angles
For an acute angle A,
- sin (90° - A) = cos A
- cos (90° - A) = sin A
- tan (90° - A) = cot A
- cot (90° - A) = tan A
- sec (90° - A) = cosec A
- cosec (90° - A) = sec A
Theorems and Laws [1]
If tan A = cot B, prove that A + B = 90°.
∵ tan A = cot B
tan A = tan (90° – B)
A = 90° – B
A + B = 90°. Proved
