| Trigonometric Functions (on Angles) | Trigonometric Ratios (of Lengths) | Mnemonics |
| \(\sin \theta \) | \[\frac{{{\rm{Opposite}}}}{{{\rm{Hypotenuse}}}}\] | SOH |
| \(\cos \theta \) | \[\frac{{{\rm{Adjacent}}}}{{{\rm{Hypotenuse}}}}\] | CAH |
| \(\tan \theta \) | \[\frac{{{\rm{Opposite}}}}{{{\rm{Adjacent}}}}\] | TOA |
Download the Notes (Mnemonics): http://db.tt/DaO9aP6Z
In the past, when calculators were not easily available, trigonometric functions/ratios were obtained from a "Trigonometric Table", as shown below.
Uses of Trigonometry
History of Trigonometry
