Mnemonic Device:

• Two Old Angels Skipped Over Heaven, Carrying Ancient Harps

Explanation: the equations for Tangent, Sine, and Cosine.

• O stands for opposite, A stands for adjacent, and H stands for hypotenuse.
  • Tangent = Opposite/Adjacent (Two Old Angels)
  • Sine = Opposite/Hypotenuse (Skipped Over Heaven)
  • Cosine = Adjacent/Hypotenuse (Carrying Ancient Harps)

Variation:

• Two Old Aunts, Sitting On Horseback, Catching A Husband. Any Old Time, Husbands Are Caught, Hail Or Shine.
  • Tangent = Opposite/Adjacent (Two Old Aunts)
    Sine = Opposite/Hypotenuse (Sitting On Horseback)
    Cosine = Adjacent/Hypotenuse (Catching A Husband)
  • Inverse functions:
    • Cosine = Adjacent/Hypotenuse (Husbands Are Caught)
    • Tangent = Opposite/Adjacent (Any Old Time)
    • Sine = Opposite/Hypotenuse (Hail Or Shine)

Additional Note: We are looking for additional information for the variation of this mnemonic (inverse functions). Do you have suggestions or corrections for this? If so, please submit a comment!