Trigonometry

Trigonometry

1. Trigonometry basics

   • Right angled Triangle
     • The triangle of most interest is the right-angled triangle.
     • We usually know another angle θ. And we give names to each side: •Adjacent is adjacent (next to) to the angle θ •Opposite is opposite the angle θ •the longest side is the Hypotenuse
     • Trigonometry is good at find a missing side or angle in a triangle
       • Sine Function: sin(θ) = Opposite / Hypotenuse Cosine Function: cos(θ) = Adjacent / Hypotenuse Tangent Function: tan(θ) = Opposite / Adjacent
   • Law of sine
     • When there is an angle opposite a side, this equation comes to the rescue. Note: angle A is opposite side a, B is opposite b, and C is opposite c.
       • Law of Sines
     • Law of cosine
       • This is the hardest to use (and remember) but it is sometimes needed to get you out of difficult situations. It is an enhanced version of the Pythagoras Theorem that works on any triangle.

2. Equations involved

3. Trigonometry functions

   • To find angle 0 in a right angled triangle
     • Sine Function: sin(θ) = Opposite / Hypotenuse
     • Cosine Function: cos(θ) = Adjacent / Hypotenuse
     • Tangent Function: tan(θ) = Opposite / Adjacent

4. Angle identification