16/4 MATH SCRIBE POST – Justin

~(•O•)~ E Math: Trigonometry Revision

CONTENT:
1. Trigonometric Functions
2. Trigonometric Rules
3. Special Angles!

*Do note that most, if not all, of these rules apply to only right angled triangles unless stated otherwise.

1. Trigonometric Functions
REVISION: Big Legged Lady
Toa (Big) – T for tangent, and O is before A.
Therefore: tan(x) = O/A
Cah (Leg) – C for cosine, and A is before H
Therefore: cos(x) = A/H
Soh (Lady/Auntie) – S for sine, and O is before H.
Therefore: sin(x) = O/H

sin^2(x) = (sin(x))^2  <–– THIS RULE applies to all trigonometric functions


2. Trigonometric Rules

1. tan(x) = sin(x) ÷ cos(x)

2. sin(90 - x) = cos(x)

cos(90 - x) = sin(x)

tan(90 - x) = 1/(tan(x)) 

3. sin^2(x) + cos^2(x) = 1

4. sin(180 - x) = sin(x)

cos(180 - x) = -cos(x)

tan(180 - x) = -tan(x)

5. PYTHAGORAS THEOREM 

a^2 + b^2 = c^2

6. Using the Z-rule 

angle of depression = angle of elevation 

3. Special Angles

Here is a table for your viewing pleasure: 

On another note you could use two triangles, 

1. Sides 1, 2, √3. 

2. Isosceles Triangle of 1, 2, and √2.