1. Trigonometry

2. Your Background familiarity with algebra and geometry Algebra Geometry
manipulating algebraic expressions
solving equations
Geometry
similar triangles
the Pythagorean theorem
a few other things

3. How to learn trigonometry
Take your time
Write things down
Draw figures
Work out the exercises

4. Applications of trigonometry
Astronomy
Geography
Physics
Engineering
Chemistry
Mathematics
Calculus
Linear algebra
Statistics

5. What is trigonometry?
from Greek trigōnon "triangle" + metron "measure"
The study of angles and of the angular relationships of planar and three-dimensional figures is known as trigonometry

6. Trigonometric functions and the unit circle