# Express Each One of the Following in Terms of Trigonometric Ratios of Angles Lying Between 0° and 45° Cot 85° + Cos 75° - Mathematics

Express each one of the following in terms of trigonometric ratios of angles lying between 0° and 45°

cot 85° + cos 75°

#### Solution

We know that cot (90^@ - theta) = tan theta and cos (90^@ - theta) = sin theta so

cot 85° + cos 75° = cot(90^@ - 5^@) + cos(90^@ - 15^@)

= tan 5^@  +sin 15^@

Thus the desired expression is tan 56^@ + sin 15^@

Concept: Trigonometric Ratios of Some Special Angles
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#### APPEARS IN

RD Sharma Class 10 Maths
Chapter 10 Trigonometric Ratios
Exercise 10.3 | Q 3.6 | Page 53