Marlene's Trigonometry Calculator Formulas and Identities  

Formulas and Identities

This page will cover the trigonometric formulas and identities used in this site.

Formulas used in this site (refer to the figure below):

  • h2   =   x2+y2
  • 90°  =  θ°+ß°  (Note: 90° is Φ° on the figure below)
  • h2    =   x2+y2   -  [2    ×    x    ×    y    ×    (Cosine Φ°)]

  • Angle θ°  =  arctangent (tangent θ)  ×  (180 / π)
  • Angle ß°  =  arctangent (tangent ß)  ×  (180 / π)
  • Angle Φ°  =  90°

  • To Convert Degrees to Radians: Radians  =  Degrees × (π / 180;)
  • To Convert Radians to Degrees: Degrees  =  Radians × (180 / π)
    Where π ≈   (i.e., PI)


Formulas for Negative Angles:
sin ( θ )  =  sin θ
cos ( θ )  =    cos θ
tan ( θ )  =  tan θ
cot ( θ )  =  cot θ
sec ( θ )  =    sec θ
csc ( θ )  =  csc θ

 
Fundamental Identities:
1  =  sin½θ+cos½θ
tan θ  =   sin θ/cos θ
cot θ  =  cos θ/sin θ
sec θ  =  1/cos θ
csc θ  =  1/sin θ