# Introduction to Trigonometry

• ### Introduction to Trigonometry

Trigonometry is an important branch of Mathematics. The word Trigonometry has been derived from three Greek words Tri (Three), Goni (Angles), Metron (Measurement). Literally it means “measurement of triangles” The origin of trigonometry have been traced back to the Egyptians of the 13 century B.C., whose tables of shadow lengths correspond to today's tangent and […]

• ### Concept of an Angle

Two rays with a common starting point from an angle. One of the rays of angle is called initial side and the other as terminal side. The angle is identified by showing the direction of rotation from the initial side to the terminal side. An angle is said to be positive/negative if the rotation is […]

• ### Measurement of Angles

The measure of an angle is the amount of rotations required to get to the terminal side from the initial side. A common measure of an angle is derived by placing its vertex at the center of a circle of some fixed radius. There are two commonly used measurements for angles: Degrees and Radians Sexagesimal […]

• ### Circular System

There is another system of angular measurement, called the Circular System. It is most useful for the study of higher mathematics. Especially in Calculus, angles are measured in radians. Radian: Radian is the measure of the angle subtended at the center of the circle by an arc, whose length is equal to the radius of […]

• ### Conversation of Radian into Degree and Vice Versa

We know that circumference of a circle of radius is , and angle formed by one complete revolution is radian, therefore, Thus we have the relationship Further Example: Convert the following angles in degree: (i) radians (ii) Solution: (i) (ii) Example: Convert into radians. Solution: Most calculators automatically would convert degree into radians and radians […]