Tiêu đề Trigonometric Functions_Lec-1 (updated).pptx ✅

TRIGONOMETRIC FUNCTIONS Introduction What is trigonometry? The word ‘trigonometry’ is derived from the Greek words ‘trigon’ and ‘metron’ and it means ‘measuring the sides of a triangle’.
TRIGONOMETRIC FUNCTIONS ANGLE Angle is a measure of rotation of a given ray about its initial point. The original ray is called the initial side and the final position of ray after rotation is called terminal side of the angle.
TRIGONOMETRIC FUNCTIONS The point of rotation is called vertex. If the direction of rotation is anti-clockwise, the angle is said to be positive and if the direction of rotation is clockwise, then the angle is negative.