Class 10th CBSE Maths

Introduction to Trigonometry

Position of a point P in the Cartesian plane with respect to co-ordinate axes is represented by the ordered pair (x, y).

Trigonometry is the science of relationships between the sides and angles of a right-angled triangle.

Trigonometric Ratios: Ratios of sides of right triangle are called trigonometric ratios.

Consider triangle ABC right-angled at B. These ratios are always defined with respect to acute angle ‘A’ or angle ‘C.

If one of the trigonometric ratios of an acute angle is known, the remaining trigonometric ratios of an angle can be easily determined.

How to identify sides: Identify the angle with respect to which the t-ratios have to be calculated. Sides are always labelled with respect to the ‘θ’ being considered

• Trigomometry from Greek trigõnon, "triangle" and metron, "measure") is a branch of mathematics that studies relationships involving lengths and angles of triangles.
• The field emerged during the 3^rd century BC from applications of geometry to astronomical studies.