Trigonometry

Trigonometry

1. Ratios

   • Sin: 180 - solution
   • Cos: 360 - Solution
   • Tan: +/- 180
   • Cosine Rule
     • a(2)=b(2)+c(2) - 2BCcosA
   • Sine Rule
     • a/sina = b/sinb = c/sinc
     • FLIP FOR ANGLES
   • Area of triangle
     • 1/2ACsinB

2. Arcs and sectors

   • Arc Length = rӨ
   • Area of a sector = ½ × θ × r2

3. HARD TRIG

   • SIN GRAPH: Start a 0, cut at 180 and 360
   • Cos Graph: Start at 1, through 90 and 270
   • Tan Graph: Asymptotes at 90 and 270
   • Cos/Sin - period of 360
   • Tan - period of 180
   • Identities
     • Sin/cos = tan
     • sin(2)+cos(2) = 1