Excel has built-in functions for sine and cosine, the two core trigonometric functions, and for hyperbolic sine and hyperbolic cosine, their hyperbolic counterparts. It also has built-in functions ...

Trigonometric identities are powerful tools for simplifying complex equations in math and science. Three core ...

Part of that is the way it's taught. Students are taught the "unit circle" and its relationship to trigonometry, but many fail to make the leap on how crucial circles are for trig functions.