What is the Tan(x) Function

The function tan(x)

$$tan(x)=\frac { opposite }{ adjacent }$$

The inverse of the function

$$tan(x)=\frac { adjacent }{ opposite }$$

Or you can also represent tan(x) by using sin(x) and cos(x)

$$tan(x)=\frac { sin(x) }{ cos(x) }$$