Trigonometry

1. Measuring angles

2. Degree measure

3. Redian measure

3.1. Relation between redian and degree

3.2. 2π radian = 360°

3.3. 1 degree = 0.01746 radian

3.3.1. Six fundamental trigonometric identities

3.3.2. sinx = 1/cosec(x)

3.3.3. cos x = 1/sec(x)

3.3.4. tan x = 1/cot(x)

3.3.5. sin2 x + cos2 x = 1

3.3.6. 1 + tan2x = sec2 x

3.3.7. 1 + cot2 x = cosec2 x

4. Angle

5. In clockwise angle is negative

6. In anticlockwise angle is positive