Trigonometry

Trigonometry

1. SOHCAHTOA

   • Split into three parts
     • SOH
       • Sin=Opposite/Hypotenuse
         • In formula triangle: Opposite on top, Sin and Hypotenuse on the bottom
     • CAH
       • Cos=Adjacent/Hypotenuse
         • In formula triangle: Adjacent on top, Cos and Hypotenuse on thebottom
     • TOA
       • Tan=Opposite/Adjacent
         • In formula triangle: Opposite on top, Tan and Adjacent on the bottom
   • Remember! Opposite, Adjacent and Hypotenuse
     • Hypotenuse is the longest side
     • Opposite: Opposite the angle you're trying to find
     • Adjacent: Next to angle you're trying to find, but the shrter of te two

2. For triangle areas

   • 1/2abSinC
     • OR 1/2*a*b*Sin C
       • TIP! Try to find half of a first

3. Sine Rule

   • a/SinA = b/SinB = c/Sin C
     • OR
       • SinA/a = SinB/b = SinC/c
         • Try to figure out which of these two should be used through trial and error

4. Cosine Rul

   • a^2=b^2+c^2-2bcCosA
     • 2bcCosA can also be written as 2*b*c*CosA
       • Remember! Read carefully and don't get a b and c mixed up