This document provides an overview of trigonometry, including its origins in Greek mathematics, the six main trigonometric functions defined in terms of right triangles, and trigonometric identities. Trigonometry is the study of triangles and relationships between sides and angles, with the six functions—sine, cosine, tangent, cotangent, secant, and cosecant—defined based on ratios of sides. Special angle values and identities are also discussed as important concepts in trigonometry.

1. TRIGONOMETRY
UNDERSTANDING TRIG FUNCTIONS AND
PRINCIPLES

3. ORIGIN
The word trigonometry comes from
the Greek words trigonon (“triangle”)
and metron (“to measure”).
Trigonometry in the modern sense
began with
the Greeks. Hipparchus (c. 190–
120 BCE) was the first to construct a
table of values for a trigonometric
function, (Brown, 2006).

4. WHAT IS TRIGONOMETRY
• According to Dalal (2013), trigonometry is the branch of mathematics that
studies triangles and the relationships between their sides and the angles
between the sides.

5. THE SIX TRIGONOMETRIC FUNTIONS
Trigonometric functions from a right triangle perspective. functions of the acute angle.
sine
cosecant
cosine
secant
tangent
cotangent

6. THE RULES
• Sin = opp/hyp
• Cos = adj/hyp
• Tan = opp/adj
• Csc = hyp/opp
• Sec = hyp/adj
• Cot = adj/opp

7. EASY WAY TO LEARN
TRIGONOMETRIC RATIOS

8. Special Angles

9. Special Angles continuation…
• The table on the previous slide shows special angles which remains the same
throughout.
• Often when asked to find a solution to a problem without using a calculator,
you will then be required to know the table of special angles by head.
• Others also use the fan method or drawing an acute triangle with the aim of
remembering the degrees and their values without the use of a calculator.

10. TRIGONOMETRIC IDENTITIES

11. TRIG IDENTITIES CONTINUATION…

12. THE END
THE END

13. REFERENCE LIST
• Barnard, R.W. & Maor, E. (2020). Trigonometry. Encyclopedia Britannica,inc.
Accessed on 17/08/2020
https://www.britannica.com/science/trigonometry
• Bhattacharya, S. (2014). Trigonometry, applications of trigonometry CBSEclass X project. SlideShare
Assessed on 17/08/2020
https://www.slideshare.net/spandanbhattacharya5/trigonometry-42340259
• Brown, A.S. (2006). The trigonometric connection: students’ understanding of sine and cosine. Proceedings 30th Conference of the International Group for the Psychology of Mathematics Education, 1, p.228.
• Dalal. D. (2013). Some applications of trigonometry. SlideShare
Assessed on 17/08/2020
https://www.slideshare.net/ddeed/some-applications-of-trigonometry-29565857
• Mswane. B.N.(2014). Trigonometry presentation. SlideShare
Assessed on17/08/2020
https://www.slideshare.net/201127223/trigonometry-presentation-32096288
• Pandy, D. (2013). Trigonometry maths school ppt. SlideShare
Assessed on 17/08/2020
https://www.slideshare.net/rashidivya/trigonometry-maths-school-ppt-2
• Pete013.(2013). Trigonometry. SlideShare
Assessed on 17/08/2020
https://www.slideshare.net/pete013/trigonometry-27881198