# Trigonometric Ratios and Identities

This topic of Trigonometry is already introduced in Standard X.

 Recollect b. given any one Trigonometric ratio, you know how to find the other ratios.

Or

sin and cos are complements of each other

tan and cot are complements of each other

sec and cosec are complements of each other

e. Simple Identities

f. Values of Trigonometric ratios of angles 0, 30Â°, 45Â°, 60Â° and 90Â°.

 sin cos tan cosec sec cot 0Â° 0 1 0 not defined 1 not defined 30Â° 2 45Â° 1 1 60Â° 2 90Â° 1 0 not defined 1 not defined 0

You have used all these properties in heights and distance problems involving right angled triangles.