From Wikipedia: "All of the trigonometric functions of an angle θ can be constructed geometrically in terms of a unit circle centered at O. Many of these terms are no longer in common use."

Nonetheless, suppose you do need to use one of these esoteric trigonometric functions that is not built into Matlab. Write a function that takes an angle as the first input (radians) and the trigonometric function name as the second input (string, function name will be completely spelled out). Make sure your function covers both the esoteric and commonly used functions; then it's a more useful tool. In particular, include sine, cosine, tangent, cosecant, secant, cotangent, versine, vercosine, coversine, covercosine, haversine, havercosine, hacoversine, hacovercosine, exsecant, excosecant, and chord. Formulas for each function are available here.