Page 3 - Trigonometry

Visualisation of Trigonometric Ratios employing a Unit

Circle
Draw a circle of unit radius with the origin because the centre.

Consider a line segment OP joining some extent P on the

circle to the centre which makes an angle θ with the x-axis.
Draw a perpendicular from P to the x-axis to chop it at Q.

• sinθ=PQ/OP=PQ/1=PQ

• cosθ=OQ/OP=OQ/1=OQ

• tanθ=PQ/OQ=sinθ/cosθ

• cosecθ=OP/PQ=1/PQ
• secθ=OP/OQ=1/OQ

• cotθ=OQ/PQ=cosθ/sinθ

Visualisation of Trigonometric Ratios employing a Unit

Circle